I've sung the praises of Learn You a Haskell
here before, but it wasn't until a few minutes ago that I discovered Learn You Some Erlang
. Different authors, but very similar styles -- writer Frederic Trottier-Hebert asked Miran Lipovaca (who brought you LYAH) if he could do a spinoff, and Miran said "of course
My favourite feature so far is the interspersing of "Don't drink too much Kool-Aid" sections throughout the text -- a handy reality check, especially for a language that's caught a lot of buzz recently (thanks, Facebook). Concurrency is rad, the actor model is the New Hotness, but that doesn't make everything else necessarily old and busted, and Trottier-Hebert is happy to tell that to you straight. Oh, and it's a lot more fun than reading the Ericsson docs, which is what I did back when I learned Erlang. If you're wondering what all the excitement is about, go learn you some Erlang and find out.
I also wonder if this is actually a new trend. What will be next? Learn You the Chomsky Hierarchy? Learn You All About Category Theory? I look forward to finding out.