Stairs, passages, light wells, the tops of fire escapes--no site is too small for a garden, or the illusion of one. This book shows you how you can create a garden in even the tiniest and most unpromising of spaces.
I didn't always understand what the author was talking about, since I'm unfamiliar with probably the majority of the plants mentioned, but I enjoyed it nonetheless. The book itself is well-designed, with bright colours and lots of large photographs incorporated into the text. Nice use of space, as you'd expect from a book about effectively using small spaces, and helpful plant suggestions for almost any situation.
My only criticism is that the author seems to assume that her readers will have both a stable environment they can manipulate as they please (eg, being able to paint things and put up or take down walls, which you generally can't do if you're renting a space); and that her readers all have enough resources to make the changes needed to produce the sorts of gardens pictured in the book, as well as the dedication and free time needed to water plants up to two times a day. Maybe all of these things are requirements for making a good garden, I don't know. It's probably best to look at this book as a source of inspiration rather than as a series of strict rules for gardening. Gardens are supposed to be enjoyable, after all.