My edition of An Illustrated Guide to Daylilies is the 2005 edition, edited by Allen McLain with illustrations by Cheryl Postlewait and Elizabeth Schreiner.
I received the little soft cover book as a free benefit (along with a quarterly AHS journal) when I signed up as a new member of the American Hemerocallis Society for an annual subscription of about $20 this year.
The book used to be entitled "Everything You've Always Wanted to Know About Daylilies" and that title is most descriptive. The compendium starts out with essays on the history of daylilies, and, then, 'What is a Daylily?' and goes on from there all the way through to the "Joy of Hybridizing" and how to register your seedlings, all complete with pictures. So by the time you are finished you have a pretty good understanding of hemerocallis and the people who love them.
I liked the book for a basic understanding of the daylily and the American Hemerocallis Society 'goings ons'. And it's well worth it to pay the $20 and join the society, too.