[ebook] Game Programming Patterns
http://gameprogrammingpatterns.com/ (also
on GitHub)
The author, Bob Nystrom, apparently worked (works?) for EA and created the
Magpie programming language so I'm pretty sure he knows his stuff. It's pretty hardcore, though, and also deals with game programming aspects that theoretically may already be taken care of for Sphere users by the engine itself, so don't go in expecting a read aimed at novice devs.
That's not to say it's not useful for Sphere users or even the few of us here developing/maintaining Sphere-compatible engines. Basically, if you have an interest in learning how a game development professional recommends organizing task-specific sections of code it will be a useful read, especially if you're a fan of the book
Design Patterns: Elements of Reusable Object-Oriented Software.