An invaluable book, originally published by Addison-Wesley (who have released their copyright -- their version of the book went out of print in the 1990s). The book describes itself as "a TeXnician's reference", and covers the way TeX (the engine) works in as much detail as most ordinary TeX programmers will ever need to know. A printed copy of the book may be had (for a modest price) via lulu.com (see the package home page for details).
Binary packages can be installed with the high-level tool pkgin (which can be installed with pkg_add) or pkg_add(1) (installed by default). The NetBSD packages collection is also designed to permit easy installation from source.
The pkg_admin audit command locates any installed package which has been mentioned in security advisories as having vulnerabilities.
Please note the vulnerabilities database might not be fully accurate, and not every bug is exploitable with every configuration.
Problem reports, updates or suggestions for this package should be reported with send-pr.