Goodness. So many.
* Learn you a Haskell - Fun for Haskell (which I've used since around 1990, but read the book anyway when it came out)
* Realm of Racket - Wonderful book. Used this to teach my son Racket at ages 7-8
* Clojure for the Brave and True - Good introduction to Clojure. Also available online for free in HTML form.
* The Art of Assembly Language - Read it a number of years ago but I recall it being very good (but unfortunately not as low level as you would think)
* Land of Lisp - I own it but haven't read it; seems to be very popular for Common Lisp, another language I have used since 1990. Also, see Practical Common Lisp (available free online)
* Ruby under a Microscope - read this when learning Ruby some time ago, but should have read it later in my Ruby career
* Understanding ECMAScript 6 - I'm not sure if this is the ES6 book I read or another one, but man, ES6 is so much better than its predecessors that it makes JavaScript fun again, and much more "functional" (which I like), especially if you use a nice library like Lodash to extend the paradigm
Others in the list I want to read and have heard good things about.
