Resources to teach fundamental design concepts to a self-taught experienced developer

I'm working remotely with a programmer who is very smart and good at hacking his way around problems, but lacks some basic concepts that are fundamental to write good software: A good grasp of modularization, what is a side effect, why global variables are bad, and so on.

I was looking for a book or online course that could help him learn these concepts:

• without being too boring (ie a basic intro book - he already knows how to program in php, javascript, ruby, SQL)


• without being too difficult/theoretical/advanced (ie not your typical university coursebook)

Any suggestions? I learned all those things a looong time ago, and a couple of hours of research on Amazon and The Google didn't bring out anything that looked what I was looking for. Thanks!