i am a fan of "how to design programs" [http://htdp.org/ http://htdp.org/] if you are already an experienced programmer, bits of it may seem trivial, but avoid

i am a fan of "how to design programs" [http://htdp.org/ http://htdp.org/] if you are already an experienced programmer, bits of it may seem trivial, but avoid the temptation to skim; following along all the way through will genuinely introduce you to the functional way of thinking.