Lambda the Ultimate

SICP gets many nods when it comes to introductory texts to programming and the study of PLs. I've been slowly working my way through SICP in a number of different PLs, most notably Oz and Alice ML. In that process, I've come across Eli Bendersky's methodical solutions to the SICP Exercises in a series of blog posts. His review of SICP is instructive of the role of the exercises:

A word about exercises in SICP. They are numerous, some of them are hard, but the exercises are the best way to really understand what the book tries to teach. In a manner, they’re as integral part of the book as the text itself. The exercises are very well prepared and lead the reader through the examples coded by the authors into greater understanding of the topics taught. At times, it feels like the exercises are specifically designed to force you to think about the essence of the topics, and not just grasp them superficially.

Highly recommended reading for anyone that is working their way through SICP. Unlike my own work, which concentrates solely on code, his explanations are quite good. He uses mostly Common Lisp for the solutions, though resorting to Scheme when it makes for more concise solutions.