I found this book on the subject: http://www.amazon.com/Physically-Based-Rendering-Second-Edition/dp/0123750792

It was published in 2010, and I was wondering if this would be a good read to learn real-time implementations for use in games. To be honest, I'd like to learn more about it, and if this book provides a good introduction to the concepts of physically-based rendering algorithms, then I'm onboard! It doesn't have to reference any APIs, but I'd prioritize OpenGL if they go into specific implementations as I'm most familiar with that API.

EDIT: After more research, it looks like a 3rd edition of the book will be arriving next year (2015).

This book is a very good read for anyone interested in designing and programming physically based rendering systems. It will walk you through the theory behind various reflectance models, radiometry, camera systems, various light sources, scattering and light transport in general.

It is not however geared towards real-time implementations, but actually walks you through the implementation of a ray tracing system. If you are looking for a book which provides you with OpenGL sample code or with everything explained in relation to OpenGL this is not the right book for you.

If you want to get a deep understanding of the theory behind physically based rendering and if you feel like you'd be able to distill and optimize a working real-time implementation out of this material then by all means go for it!

This is exactly the kind of answer I'm looking for. I suspect that physically-based rendering is becoming more standard for AAA titles --for even consoles nowadays, and we're even seeing it with Unity, which is heavily used in the Indie scene. That said, I'd like to learn the fundamentals, and learn about real-time implementations of it in more of a derivative form with out ALL of the theory so I can at least get something usable. I suspect the real-time approaches aren't necessarily true raytracers. Do you know of any books on real-time raytracing that helpful?

When we're talking about OpenGL we're in the realm of rasterization, not ray tracing.

Yeah, I know. That was poorly-worded on my part. Until then, I'll keep learning modern OpenGL, and I'll check out the SIGGRAPH resources Hodgman posted.