Author: Dan Saffer
Publisher: O'Reilly, 2008
Pages: 272
ISBN: 978-0596518394
Aimed at: Anyone wanting to think deeply about the gestural interface
Rating: 3
Pros: Wide discussion
Cons: Not practical nor in depth
Reviewed by: Sue Gee

I enjoyed reading this book but you might not if you expect it to tell you how to implement gestural interfaces. There isn't a single line of code in the book and in a book that is less than 18 months old you might wonder why there isn't more coverage of recent hardware and software. For a practical programming book this would be a serious criticism but this particular book is more about the whole idea of gestural interfaces.

It starts off with an overview of the idea and a short history. Chapter Two then goes into the anatomy of the human body with pretty diagrams of how joints work taken from Grey's Anatomy. This isn't really necessary but it starts you thinking more widely about gestures and how they relate to the particular input device in use.

Chapter Three lists patterns for touchscreen and interactive surfaces. Each of the patterns follows the same structure - What, Use When, Why, How and Examples. This isn't deep but if you haven't thought about the whole world of gestural commands then it is helpful. Chapter Four repeats the exercise for free-form input and includes whole body movements - such as Step to Activate.

Chapter Five deals with the fascinating problem of documenting gesture and notating body movements in general. This is interesting but not essential to most programmers' thinking about gestural interfaces. Chapter Six deals with prototyping and again it doesn't really get to grips with the sort of prototyping a programmer might think up - it's more about making models and paper prototypes. Chapter Seven is about communicating interactive gestures and how to provide written instructions, demonstrations and symbols that work. The final chapter is a look to the future and it is extremely general. An appendix provides a palette of human gestures and movements.

Overall the book is a well-educated look at the whole subject of gestural interfaces and it isn't focused down onto one particular manifestation of the idea like the iPhone, say. As such it provides interesting background reading and it might even provoke you to think harder about how you might use gesture to communicate with a machine - and not necessarily just a computer or a phone.

The one area that is raised in the book but not fully discussed is the notion of the ethics of gesture and the idea that some gestures might be considered rude or crude in some cultures. Similarly there isn't quite enough exploration of the way that some gestures seem to be natural when using a device and enhance the overall user experience almost to the point of being addictive - for example the two-finger zoom seems to almost connect you to the image being manipulated.

A good if slightly academic introduction to the phenomenon that is the gestural interface, but not a book if you are looking for a practical guide to implementation.