Over several weeks I've been reading 37signals' (makers of web apps Basecamp and Highrise) book Getting Real. The whole book can be read online at http://gettingreal.37signals.com/toc.php.
The book describes 37signals' design and operating philosophy, based on their experience working in small teams to design software. The book is easy to read: there's no code, each chapter is divided into bite-size essays, the book is well-written and a lot of the advice really makes sense, especially if you have read anything about "agile" processes previously.
37signals has well-deserved credibility, as their apps are fairly successful and can be used as prime examples of...