A reference 62

I wanted this book a long time but saw the price ... I enjoyed myself in recently acquiring.
It is a real gem for anyone who wants to better understand the functioning of TeX.
The only downside is probably in exercises ... some require knowledge that only appear in the following chapters, more difficult; say this is what makes the charm: it satisfied his thirst for knowledge by dipping in sometimes distant sources.
A big thank you to Mr. Knuth for this wonderful book and all it has shared!