diff --git a/CHANGELOG.md b/CHANGELOG.md
index ad1e8e63..8b8f1327 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@ Change Log -- Ray Tracing in One Weekend
 # v3.1.1 (in progress)
 
 ### _In One Weekend_
+  - Fix: Camera initialization with explicit up vector (#537)
   - Change: The C++ `<random>` version of `random_double()` no longer depends on `<functional>`
     header.
   - Change: Refactored `random_scene()`. More named intermediate values, sync'ed with source.
diff --git a/books/RayTracingInOneWeekend.html b/books/RayTracingInOneWeekend.html
index ebd77a1f..4808f462 100644
--- a/books/RayTracingInOneWeekend.html
+++ b/books/RayTracingInOneWeekend.html
@@ -2669,7 +2669,7 @@
 This allows us to change the viewpoint:
 
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C++
-    camera cam(point3(-2,2,1), point3(0,0,-1), vup, 90, aspect_ratio);
+    camera cam(point3(-2,2,1), point3(0,0,-1), vec3(0,1,0), 90, aspect_ratio);
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     [Listing [scene-free-view]: <kbd>[main.cc]</kbd> Scene with alternate viewpoint]