Absolute BSD

The Ultimate Guide to FreeBSD

2002

Absolute FreeBSD

The Complete Guide to FreeBSD

2007

Absolute OpenBSD

Unix for the Practical Paranoid

2003

Cisco Routers for the Desperate

Router Management, the Easy Way

2004

FreeBSD Mastery

ZFS

2015

Networking for Systems Administrators

2015

PGP & GPG

Email for the Practical Paranoid

2006

SSH Mastery

OpenSSH, PuTTY, Tunnels and Keys

2012

Sudo Mastery

User Access Control for Real People

2013

TLS Mastery

Tux edition

2021

Tarsnap Mastery

Online Backups for the Truly Paranoid

2015