This is very good documentation. In my technical writing activities I have learned that there are two kinds of bad documentation: Math textbooks ("Prove X. Lemm

This is very good documentation. In my technical writing activities I have learned that there are two kinds of bad documentation: Math textbooks ("Prove X. Lemma: ..." [Why are we proving this anyway?]) and cooking recipes ("Do a, b, c, the end" [What if I need to cook something else?]) - too little practice or too little theoretical foundation. Sometimes both are present but too disjoint, or the theory is badly structured. This one does a great job at introducing the foundations, in the right order, and immediately showing what they mean to you in practice.