Getting to Know the XSL Family of Standards: A Review of The XSL Companion
http://www.stcboston.org/archives/broadside/2001-01/cj_boeri_xsl-2000_final.shtml

Boeri, Bob
Boston Broadside
2001

Abstract:

If you need to learn XSL, or think it might be a career-enhancing move, there are currently very few books that describe XSL. In fact, some of these books can be overwhelming in size and in programming detail. The XSL Companion is different, and, I feel, aptly named a 'companion'.