This is the book in the ever popular '...for dummies' series tackling bass guitar, taking you from a complete novice to someone with a knowledge of various styles and sounds.
It is written in the usual style for the series, so nicely layed out for reading through and in a fairly informal easygoing style, To me in two main sections - playing bass, and everything else. This book is by no means an advanced guide to all that bass playing offers, but will give you a good solid knowledge of playing various styles - basic scales and solo work, rock, swing, funk, etc... The other main theme is the more technical side to bass, thoughts behind looking to buying a bass and other equipment, and basic maintenence and setups to keep it working. There is also a smaller section at the end of 'The part in tens', here describing ten well respected and talented bassists, and ten great rhythm sections to look into more to hear some professionals at it.
I got this book as someone with a decent enough practical knowledge of how to play bass, but virtually no theory, and this book takes you simply through the basics of theory and how it applies to bass, then into more specific ideas for particular styles, and has stood me well in my knowledge.
This book also comes with a cd letting you hear all the examples of playing out loud which is great for giving you an idea of what stuff is supposed to sound like (especially relating to rhythms and notation)
One other handy section it does include is a reference page of scales and the ordering of the notes inside the front page, and a few pages of blank tab/musical notation for you to doodle down notes yourself on.
For a newcomer to bass, or someone wanting to learn the basics of theory and more information of various different styles, this is a great book and a good resource.