Carla Schroder is the Delia Smith of Linux cookbooks; all the recipes work and can be tried at home.
However this work is a little dated for something so recently published (for instance PCI Express is treated as an up-and-coming technology rather than the current standard).
Her SAMBA example is about replacing an NT4 domain controller, which although a perfectly workable solution for home and small business is a little out of date given that AD is now in it's 8th year.
There is also some confusion between MB/s and Mbps that leaves you thinking that PCI can't handle Gigabit Ethernet.
Notwithstanding the above comments it is a good book. It encourages you to try all those things you said you'd do when you had time. Because it's a cookbook you can do most 'recipes' in anything from an hour to an afternoon. I've just got the book but I'll try most of the ideas over the next month or so, so I might finally have a vpn that works, a DC for my 6 pc home network and a firewall that I understand how to configure.