Anyone that's had to administer sendmail for any length of time probably has a copy of O'Reilly's Sendmail. While this book is comprehensive, and provides you a comprehensive listing of every knob to be turned and button to be pushed, the main thrust is in telling you all the options for various features, and not in providing a basic walkthrough on setting up and using some of the features.
Craig Hunt's Sendmail Cookbook provides a handful of "recipies" for doing some useful stuff in sendmail, starting with runthroughs of the build process, and covering topics like using external sources like NIS and LDAP to pull aliases, SPAM, SMTPAUTH and TLS/SSL, and queue management, to list some of the chapters. Each chapter starts with a brief overview (a couple of pages) of the topic, and then a series of sections that provide some task to be done (e.g. Configure masquerading to hide only hosts that are specifically identified for masquerading), a solution, and then a more in-depth discussion of what was done, alternative ways to accomplish the task, and sometimes some testing/debugging examples.
Unfortunately, while I had several sections (LDAP support, queue groups) that I was going to make good use of, I ended up changing jobs (to someplace that runs Postfix) before I had a chance to really work on implementing most of them, but what I did use there (the TLS/SSL setup and configuration sections) was clear and pretty easy to follow. Some of the sections, also, seemed to be fairly basic stuff (a lot of the sections on masquerading, for instance), though it may be that those sections were ones I was already pretty familiar with, and so didn't get much from them.
For admins that mostly just need the bat book to help them with any sendmail issues/questions, this book may not be worthwhile, but for people that are looking for walkthroughs of setting up and using various features of sendmail, they should definitely check this out.