"A major, perhaps foolhardy, undertaking. "---JEmacs Paper

I've already praised Per Bothner's programming skills, but it's also important to note that he does a fine job of documenting his work. In addition to the standard style documentation he provides for his programs, he's written a number of papers about the stuff he's worked on (I recommend his Kawa paper, although his Smalltalk in Java note is quite interesting).

The JEmacs paper is worth reading for the high level view Bothner gives of his Quixotic effort. It's a valuable peek at the design, implementation, and optimization strategies and tactics of a master programmer facing a daunting task.