diff --git a/CHANGELOG.md b/CHANGELOG.md
index 34b07267..add361d4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,7 @@ Change Log -- Ray Tracing in One Weekend
   - Change: `hittable` member variable `ptr` renamed to `object`
   - Change: general rename of `mat_ptr` to `mat` (material)
   - Change: hittable::bounding_box() signature has changed to always return a value (#859)
+  - Fix: Enabled compiler warnings for MSVC, Clang, GNU. Cleaned up warnings as fit (#865)
 
 ### In One Weekend
   - Added: More commentary about the choice between `double` and `float` (#752)
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 969de878..5c64a8a4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,6 +17,8 @@ set ( CMAKE_CXX_EXTENSIONS        OFF )
 set ( COMMON_ALL
   src/common/rtweekend.h
   src/common/camera.h
+  src/common/color.h
+  src/common/interval.h
   src/common/ray.h
   src/common/vec3.h
 )
@@ -71,6 +73,28 @@ set ( SOURCE_REST_OF_YOUR_LIFE
   src/TheRestOfYourLife/main.cc
 )
 
+include_directories(src/common)
+
+# Specific Compiler Flags
+
+message (STATUS "Compiler ID: " ${CMAKE_CXX_COMPILER_ID})
+
+if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+    add_compile_options("/we 4265") # Class has virtual functions, but its non-trivial destructor is not virtual
+    add_compile_options("/w3 5038") # Data member will be initialized after [other] data member
+    add_compile_options("/we 5204") # Class has virtual functions, but its trivial destructor is not virtual
+elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    add_compile_options(-Wnon-virtual-dtor) # Class has virtual functions, but its destructor is not virtual
+    add_compile_options(-Wreorder) # Data member will be initialized after [other] data member
+    add_compile_options(-Wmaybe-uninitialized) # Variable improperly initialized
+    add_compile_options(-Wunused-variable) # Variable is defined but unused
+elseif (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    add_compile_options(-Wnon-virtual-dtor) # Class has virtual functions, but its destructor is not virtual
+    add_compile_options(-Wreorder) # Data member will be initialized after [other] data member
+    add_compile_options(-Wsometimes-uninitialized) # Variable improperly initialized
+    add_compile_options(-Wunused-variable) # Variable is defined but unused
+endif()
+
 # Executables
 add_executable(inOneWeekend      ${SOURCE_ONE_WEEKEND})
 add_executable(theNextWeek       ${SOURCE_NEXT_WEEK})
@@ -82,5 +106,3 @@ add_executable(pi                src/TheRestOfYourLife/pi.cc                ${CO
 add_executable(estimate_halfway  src/TheRestOfYourLife/estimate_halfway.cc  ${COMMON_ALL})
 add_executable(sphere_importance src/TheRestOfYourLife/sphere_importance.cc ${COMMON_ALL})
 add_executable(sphere_plot       src/TheRestOfYourLife/sphere_plot.cc       ${COMMON_ALL})
-
-include_directories(src/common)
diff --git a/books/RayTracingInOneWeekend.html b/books/RayTracingInOneWeekend.html
index d4917ca3..007a4f69 100644
--- a/books/RayTracingInOneWeekend.html
+++ b/books/RayTracingInOneWeekend.html
@@ -867,6 +867,8 @@
 
     class hittable {
       public:
+        virtual ~hittable() = default;
+
         virtual bool hit(const ray& r, double ray_tmin, double ray_tmax, hit_record& rec) const = 0;
     };
 
@@ -2033,6 +2035,8 @@
 
     class material {
       public:
+        virtual ~material() = default;
+
         virtual bool scatter(
             const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered) const = 0;
     };
diff --git a/books/RayTracingTheNextWeek.html b/books/RayTracingTheNextWeek.html
index 1022b1c8..bb89864e 100644
--- a/books/RayTracingTheNextWeek.html
+++ b/books/RayTracingTheNextWeek.html
@@ -1099,6 +1099,8 @@
 
     class texture {
       public:
+        virtual ~texture() = default;
+
         virtual color value(double u, double v, const point3& p) const = 0;
     };
 
@@ -1194,8 +1196,8 @@
 
       public:
         double inv_scale;
-        shared_ptr<texture> odd;
         shared_ptr<texture> even;
+        shared_ptr<texture> odd;
     };
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     [Listing [checker-texture]: <kbd>[texture.h]</kbd> Checkered texture]
@@ -2293,12 +2295,15 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
     class material {
       public:
+        ...
+
+
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
         virtual color emitted(double u, double v, const point3& p) const {
             return color(0,0,0);
         }
-
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
+
         virtual bool scatter(
             const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered
         ) const = 0;
@@ -2466,8 +2471,8 @@
         aabb bounding_box() const override { return bbox; }
 
       public:
-        shared_ptr<material> mat;
         double x0, x1, y0, y1, k;
+        shared_ptr<material> mat;
         aabb bbox;
     };
 
@@ -2590,8 +2595,8 @@
         aabb bounding_box() const override { return bbox; }
 
       public:
-        shared_ptr<material> mat;
         double x0, x1, z0, z1, k;
+        shared_ptr<material> mat;
         aabb bbox;
     };
 
@@ -2625,8 +2630,8 @@
         aabb bounding_box() const override { return bbox; }
 
       public:
-        shared_ptr<material> mat;
         double y0, y1, z0, z1, k;
+        shared_ptr<material> mat;
         aabb bbox;
     };
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -3120,8 +3125,8 @@
 
       public:
         shared_ptr<hittable> boundary;
-        shared_ptr<material> phase_function;
         double neg_inv_density;
+        shared_ptr<material> phase_function;
     };
 
     #endif
diff --git a/books/RayTracingTheRestOfYourLife.html b/books/RayTracingTheRestOfYourLife.html
index 453ba0b3..4956e7bf 100644
--- a/books/RayTracingTheRestOfYourLife.html
+++ b/books/RayTracingTheRestOfYourLife.html
@@ -212,7 +212,6 @@
             }
         }
 
-        auto N = static_cast<double>(sqrt_N) * sqrt_N;
         std::cout << std::fixed << std::setprecision(12);
         std::cout
             << "Regular    Estimate of Pi = "
@@ -886,7 +885,7 @@
 
         // Find out the sample at which we have half of our area
         double half_sum = sum / 2.0;
-        double halfway_point;
+        double halfway_point = 0.0;
         double accum = 0.0;
         for (int i = 0; i < N; i++){
             accum += samples[i].p_x;
@@ -1504,9 +1503,7 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
     class material {
       public:
-        virtual color emitted(double u, double v, const point3& p) const {
-            return color(0,0,0);
-        }
+        ...
 
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
@@ -2305,6 +2302,9 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
     class material {
       public:
+        ...
+
+
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
         virtual color emitted(
             const ray& r_in, const hit_record& rec, double u, double v, const point3& p
@@ -2312,7 +2312,6 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
             return color(0,0,0);
         }
-
         ...
     };
 
@@ -2523,21 +2522,21 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
     class hittable_pdf : public pdf {
       public:
-        hittable_pdf(const hittable_list& _hittable_ptr, const point3& _origin)
-          : hittable_ptr(_hittable_ptr), origin(_origin)
+        hittable_pdf(const hittable_list& _objects, const point3& _origin)
+          : objects(_objects), origin(_origin)
         {}
 
         double value(const vec3& direction) const override {
-            return hittable_ptr->pdf_value(origin, direction);
+            return objects.pdf_value(origin, direction);
         }
 
         vec3 generate() const override {
-            return hittable_ptr->random(origin);
+            return objects.random(origin);
         }
 
       public:
+        const hittable_list& objects;
         point3 origin;
-        shared_ptr<hittable> hittable_ptr;
     };
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     [Listing [class-hittable-pdf]: <kbd>[pdf.h]</kbd> The hittable_pdf class]
@@ -2555,9 +2554,7 @@
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
     class hittable {
       public:
-        virtual bool hit(const ray& r, interval ray_t, hit_record& rec) const = 0;
-
-        virtual aabb bounding_box() const = 0;
+        ...
 
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
@@ -2890,11 +2887,7 @@
 
     class material {
       public:
-        virtual color emitted(
-            const ray& r_in, const hit_record& rec, double u, double v, const point3& p
-        ) const {
-            return color(0,0,0);
-        }
+        ...
 
         virtual bool scatter(
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++ highlight
@@ -2903,11 +2896,7 @@
         ) const {
             return false;
         }
-
-        virtual double scattering_pdf(const ray& r_in, const hit_record& rec, const ray& scattered)
-        const {
-            return 0;
-        }
+        ...
     };
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     [Listing [material-refactor]: <kbd>[material.h]</kbd> Refactoring the material class]
diff --git a/src/InOneWeekend/hittable.h b/src/InOneWeekend/hittable.h
index 6c9bb916..4ef172cc 100644
--- a/src/InOneWeekend/hittable.h
+++ b/src/InOneWeekend/hittable.h
@@ -33,6 +33,8 @@ class hit_record {
 
 class hittable {
   public:
+    virtual ~hittable() = default;
+
     virtual bool hit(const ray& r, interval ray_t, hit_record& rec) const = 0;
 };
 
diff --git a/src/InOneWeekend/material.h b/src/InOneWeekend/material.h
index f3c5ff1e..01d58bae 100644
--- a/src/InOneWeekend/material.h
+++ b/src/InOneWeekend/material.h
@@ -19,6 +19,8 @@ class hit_record;
 
 class material {
   public:
+    virtual ~material() = default;
+
     virtual bool scatter(
         const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered
     ) const = 0;
diff --git a/src/TheNextWeek/aarect.h b/src/TheNextWeek/aarect.h
index 4eb84c3a..f992e455 100644
--- a/src/TheNextWeek/aarect.h
+++ b/src/TheNextWeek/aarect.h
@@ -49,8 +49,8 @@ class xy_rect : public hittable {
     aabb bounding_box() const override { return bbox; }
 
   public:
-    shared_ptr<material> mat;
     double x0, x1, y0, y1, k;
+    shared_ptr<material> mat;
     aabb bbox;
 };
 
@@ -88,8 +88,8 @@ class xz_rect : public hittable {
     aabb bounding_box() const override { return bbox; }
 
   public:
-    shared_ptr<material> mat;
     double x0, x1, z0, z1, k;
+    shared_ptr<material> mat;
     aabb bbox;
 };
 
@@ -127,8 +127,8 @@ class yz_rect : public hittable {
     aabb bounding_box() const override { return bbox; }
 
   public:
-    shared_ptr<material> mat;
     double y0, y1, z0, z1, k;
+    shared_ptr<material> mat;
     aabb bbox;
 };
 
diff --git a/src/TheNextWeek/constant_medium.h b/src/TheNextWeek/constant_medium.h
index ed239f2a..57991546 100644
--- a/src/TheNextWeek/constant_medium.h
+++ b/src/TheNextWeek/constant_medium.h
@@ -79,8 +79,8 @@ class constant_medium : public hittable {
 
   public:
     shared_ptr<hittable> boundary;
-    shared_ptr<material> phase_function;
     double neg_inv_density;
+    shared_ptr<material> phase_function;
 };
 
 
diff --git a/src/TheNextWeek/hittable.h b/src/TheNextWeek/hittable.h
index 9dd3ee8d..37829e28 100644
--- a/src/TheNextWeek/hittable.h
+++ b/src/TheNextWeek/hittable.h
@@ -38,6 +38,8 @@ class hit_record {
 
 class hittable {
   public:
+    virtual ~hittable() = default;
+
     virtual bool hit(const ray& r, interval ray_t, hit_record& rec) const = 0;
 
     virtual aabb bounding_box() const = 0;
diff --git a/src/TheNextWeek/material.h b/src/TheNextWeek/material.h
index 47087b68..e013d5b1 100644
--- a/src/TheNextWeek/material.h
+++ b/src/TheNextWeek/material.h
@@ -19,6 +19,8 @@
 
 class material {
   public:
+    virtual ~material() = default;
+
     virtual color emitted(double u, double v, const point3& p) const {
         return color(0,0,0);
     }
diff --git a/src/TheRestOfYourLife/aarect.h b/src/TheRestOfYourLife/aarect.h
index 3162ed3b..895f5880 100644
--- a/src/TheRestOfYourLife/aarect.h
+++ b/src/TheRestOfYourLife/aarect.h
@@ -49,8 +49,8 @@ class xy_rect : public hittable {
     aabb bounding_box() const override { return bbox; }
 
   public:
-    shared_ptr<material> mat;
     double x0, x1, y0, y1, k;
+    shared_ptr<material> mat;
     aabb bbox;
 };
 
@@ -105,8 +105,8 @@ class xz_rect : public hittable {
     }
 
   public:
-    shared_ptr<material> mat;
     double x0, x1, z0, z1, k;
+    shared_ptr<material> mat;
     aabb bbox;
 };
 
@@ -143,8 +143,8 @@ class yz_rect : public hittable {
 
     aabb bounding_box() const override { return bbox; }
   public:
-    shared_ptr<material> mat;
     double y0, y1, z0, z1, k;
+    shared_ptr<material> mat;
     aabb bbox;
 };
 
diff --git a/src/TheRestOfYourLife/estimate_halfway.cc b/src/TheRestOfYourLife/estimate_halfway.cc
index 23f02622..9e5f0332 100644
--- a/src/TheRestOfYourLife/estimate_halfway.cc
+++ b/src/TheRestOfYourLife/estimate_halfway.cc
@@ -48,7 +48,7 @@ int main() {
 
     // Find out the sample at which we have half of our area
     double half_sum = sum / 2.0;
-    double halfway_point;
+    double halfway_point = 0.0;
     double accum = 0.0;
     for (int i = 0; i < N; i++){
         accum += samples[i].p_x;
diff --git a/src/TheRestOfYourLife/hittable.h b/src/TheRestOfYourLife/hittable.h
index 8eb58f8e..4ffe55ec 100644
--- a/src/TheRestOfYourLife/hittable.h
+++ b/src/TheRestOfYourLife/hittable.h
@@ -38,6 +38,8 @@ class hit_record {
 
 class hittable {
   public:
+    virtual ~hittable() = default;
+
     virtual bool hit(const ray& r, interval ray_t, hit_record& rec) const = 0;
 
     virtual aabb bounding_box() const = 0;
diff --git a/src/TheRestOfYourLife/integrate_x_sq.cc b/src/TheRestOfYourLife/integrate_x_sq.cc
index cff8f889..dafc7b04 100644
--- a/src/TheRestOfYourLife/integrate_x_sq.cc
+++ b/src/TheRestOfYourLife/integrate_x_sq.cc
@@ -25,8 +25,6 @@ double pdf(double x) {
 }
 
 int main() {
-    int inside_circle = 0;
-    int inside_circle_stratified = 0;
     int N = 1;
 
     auto sum = 0.0;
diff --git a/src/TheRestOfYourLife/material.h b/src/TheRestOfYourLife/material.h
index b143b3c5..665b8195 100644
--- a/src/TheRestOfYourLife/material.h
+++ b/src/TheRestOfYourLife/material.h
@@ -28,6 +28,8 @@ class scatter_record {
 
 class material {
   public:
+    virtual ~material() = default;
+
     virtual color emitted(
         const ray& r_in, const hit_record& rec, double u, double v, const point3& p
     ) const {
diff --git a/src/TheRestOfYourLife/pdf.h b/src/TheRestOfYourLife/pdf.h
index c006cc82..31f8291e 100644
--- a/src/TheRestOfYourLife/pdf.h
+++ b/src/TheRestOfYourLife/pdf.h
@@ -45,21 +45,21 @@ class cosine_pdf : public pdf {
 
 class hittable_pdf : public pdf {
   public:
-    hittable_pdf(const hittable_list& _hittable_ptr, const point3& _origin)
-      : hittable_ptr(_hittable_ptr), origin(_origin)
+    hittable_pdf(const hittable_list& _objects, const point3& _origin)
+      : objects(_objects), origin(_origin)
     {}
 
     double value(const vec3& direction) const override {
-        return hittable_ptr.pdf_value(origin, direction);
+        return objects.pdf_value(origin, direction);
     }
 
     vec3 generate() const override {
-        return hittable_ptr.random(origin);
+        return objects.random(origin);
     }
 
   public:
+    const hittable_list& objects;
     point3 origin;
-    const hittable_list& hittable_ptr;
 };
 
 
diff --git a/src/TheRestOfYourLife/pi.cc b/src/TheRestOfYourLife/pi.cc
index 5f03eb37..18de8a84 100644
--- a/src/TheRestOfYourLife/pi.cc
+++ b/src/TheRestOfYourLife/pi.cc
@@ -38,7 +38,6 @@ int main() {
         }
     }
 
-    auto N = static_cast<double>(sqrt_N) * sqrt_N;
     std::cout << std::fixed << std::setprecision(12);
     std::cout << "Regular    Estimate of Pi = "
         << (4.0 * inside_circle) / (sqrt_N*sqrt_N) << '\n';
diff --git a/src/common/texture.h b/src/common/texture.h
index 9bed30a3..ee3bc984 100644
--- a/src/common/texture.h
+++ b/src/common/texture.h
@@ -19,6 +19,8 @@
 
 class texture {
   public:
+    virtual ~texture() = default;
+
     virtual color value(double u, double v, const point3& p) const = 0;
 };
 
@@ -65,8 +67,8 @@ class checker_texture : public texture {
 
   public:
     double inv_scale;
-    shared_ptr<texture> odd;
     shared_ptr<texture> even;
+    shared_ptr<texture> odd;
 };