I've been using the vi and Vim editors since about 1998. It's an incredibly complex topic. I've tried to read books about it before, but this is the first one that's really connected with me and, while I skipped the first fifty or so pages because I knew the introductory stuff, I read the remaining 280 pages - including parts of the Appendix. Drew Neil is relatively well known in the Vim world as the man behind vimcasts.org.
The book works because it starts with the simplest instructions and methods, each wrapped in a very short chapter. Each is self-contained and well explained. As you continue, they become more complex and build upon previous examples. It's a simple formula, but many technical books - even ones that set out to follow it - fail to make it work. I learned a great deal about my favourite editor: highly recommended.