I apologize for being a bit off-topic, but I’m starting a new WebGL Insights book on intermediate and advanced WebGL topics similar to what we did with OpenGL Insights. We just released the call for authors and I appreciate help spreading the word on twitter and so on:
Given how widely used WebGL is for geospatial, I hope we’ll see a few geospatial articles in the book. 
Thanks!
Patrick
Hey Patrick,
Which books would you recommend on WebGL in terms of the development one would do on Cesium? I’m looking to buy and read something but there’s so much out there, especially in terms of threeJS. What would you recommend for WebGL and mapping? Also…when is your book coming out? I’m super excited about it!
Vanessa,
I have not read it, but for general WebGL, I suspect the WebGL Programming Guide is good:
http://www.amazon.com/WebGL-Programming-Guide-Interactive-Graphics/dp/0321902920
For Cesium, we abstract away WebGL so most developers working on Cesium do not use it directly. We have this list of recommended reading.
WebGL Insights will be out in August.
Patrick