recently the The Joy of TeX was added to CTAN. From the TeX Catalogue:
User documentation for the AMS-TeX macro collection. This distribution makes the full text of the most recent reprint of the second edition of "The Joy of TeX" by Michael Spivak available for the first time, as a pdf file: joyt2.pdf. "Joy" is the user documentation for AMS-TeX. (Please note that AMS-TeX is no longer supported by the AMS, nor is it used by the AMS publishing program.)
joyt2.pdf -- The Joy of TeX, second edition: A Gourmet guide to typesetting with the AMS-TeX macro package, by M. D. Spivak. This is the final edition, printed with corrections by the American Mathematical Society in 2004. Any material in this guide may be reproduced or duplicated for personal or educational use.
It cannot be included in TeX Live proper, but for those who are interested, here is a link to the CTAN package:
https://ctan.org/pkg/joy-of-texand it is also in tlcontrib
http://contrib.texlive.info/from where you can install it.