Presented here are a number of essays on lean software. Less an introduction to the concept, the book is more musings with a theme. That said, there are introductions to some of the aspects of Kanban and how they are being applied to software (after their original application to manufacturing). Also included are thoughts on the best ways to do things in a Kanban system - the proper layout of the big board, how big a team the system (and variations on the system) can support, how small a portion of work should be to keep things moving. Most of these concepts are built upon in a "try it, see what works, adjust, see what improves" manner.
That said, without some experience with software development systems going in, this book may be incomprehensible. Too often, terms are defined many pages after they're used and the author sometimes takes for granted that his audience has instant access to some knowlege that they may not. Essentially, as a series of linkified blog posts, this would be much easier to read, but as a published work, editing in some exposition might have made this easier reading.