Greg Lehey, The Complete FreeBSD: Documentation from the Source
ISBN: 0596005164 | edition 2003 | PDF | 639 pages | 9 mb
FreeBSD is by far the most popular version of BSD, the legendary operating system that has contributed a great deal to every version of Unix® in use today (including Mac OS® X). Originally a community effort by the University of California at Berkeley, FreeBSD was aimed at making Unix a little friendlier and easier to use. By the time other free operating systems came along, BSD was firmly established and very reliable. And it continues to be today.