Presentation Zen Design is an excellent book, geared for people who want to build impactful presentations but lack a deep design background.
Garr's first book, Presentation Zen, did an impressive job at giving an overview of what makes for a great presentation. He covered preparation, crafting the story, basic design principles and delivery strategies along with a nice selection of sample slides.
This book expands significantly on the first book's design section and this is a good thing. Once you've made the decision to move beyond typical PowerPoints it's great to have a book filled with so much practical information and lots of examples. With sections on type, color, images, video, layout and presenting data (an area where so many of the presentations I see fall apart), Presentation Zen Design provides a comprehensive toolkit for creating compelling presentations.