Thanks to Derrick, who suggested a blog about essential management books for web designers, especially those just starting out.
A list follows. It emphasizes old-fashioned approaches to management, the tried and true, as these have made all the difference to me. Please post your additions, with a brief reason why you recommend it. That way, this site can have one location with some great book suggestions.
Marketing and Sales:
The Web Design Business Kit, Brendon Sinclair. Where else can you get a marketing and sales book for web designers, written by a successful web designer?
The IT Business Acceleration Manual, yours truly. See the following Sitepoint link for a comparison with Brendon