language agnostic - Literature and tutorials for writing a ray tracer

Question

I am interested in finding recommendations on books on writing a raytracer, simple and clear implementations of ray tracing that can be seen on the web, and online resources on introductory ray tracing.

Ideally, the approach would be incremental and tutorial in style, and explain both the programming techniques and underyling mathematics, starting from the basics.

Answer 1

"Ray Tracing from the Ground Up" by Kevin Suffern for getting started.

"Physically Based Rendering" by Matt Pharr and Greg Humphreys for a more advanced take on it when you've gotten comfortable with the basics.

And if you get really into it, the Ray Tracing News archives are a good read. Also, a lot of ray tracing enthusiast hang out at the ompf2.com forum.