This book is starting to get a little bit old (it was written in 2005) but it is still a great introduction to the complexities and potential fun with mapping online.
The book starts with general concepts, wades through command line and desktop tools for mapping, dives into Web Map Services based on the MapServer project, and finishes off with more reference material in the appendixes. The general concepts, command line tools (page 82 and nearby), and references will be useful for years to come. The rest of the material was a bit dated. For example, page 132 has a sidebar exclaiming that the **new* GMaps service from Google seemed very interesting.
I was particularly impressed by
* The introduction to SFSQL (Simple Feature Structured Query Language) on page 242
* The introduction to PostGIS features in Chapter 13 including guide to querying on page 256
* Discussion of the ogr and gdal tools for dealing with various types of data.
I really hope that O'Reilly will update this book and that the author will be able to expand it to cover other mapping tools beyond MapServer and other databases beyond PostgreSQL (we mostly use MySQL).
