From an email to a coworker about what books I'd recommend to learn to program:

The only programming book I picked up recently was "Programming C#" or some such by Jesse Liberty from O'Reilly. Unfortunately at this point, I'm usually able to surf a few sites and figure out how to do whatever in whichever programming language as long as I have a language reference laying around somewhere. I've enjoyed O'Reilly's "Nutshell" books on Java, which are basically just lang refs printed out, and would like to get the same thing for C# if I ever have a real reason to learn the language.

Once you've gotten a good feel for one language (like you've done with Crystal scripting), it might be worth finding a pretty good week-long, relatively high-level training course on the language you'd like to learn. That's all I did for VB6 a few years ago. Every language is just a dialect of the same "archetypal" [programming] language, if you ask me. Programming in a new language as much learning your new IDE as learning the API of the lang nowadays.