The book is split into eight chapters, each chapter containing a number of useful tips explained in easy to understand language and with examples throughout. The chapters are:
1 - Reducing Workbook and Worksheet Frustration
A collection of tips to improve your general efficiency using Excel, such as how to enter data into multiple worksheets at once and how to reduce the file size of bloated Excel documents.
2 - Hacking Excel's Built-In Features
Tops on advanced uses of Excel's built-in functions that help you wring the absolute best functionality out of them. Includes the likes of hilighting every other row or column, and supporting multiple lists in a combo-box.
3 - Naming Hacks
A collection of hacks based on defined names, including probably the most searched for: how to create named ranges that expand and contract automatically to fit the data.
4 - Hacking PivotTables
Starts with an explanation of PivotTables and how to use them, then goes intoa few tips on more advanced usage such as automating pivot-table creation.
5 - Charting Hacks
Some great hacks in here, including how to put two different styles on one chart (ie a bar chart with a line chart overlayed), and how to create pivot-table like functionality with basic charts.
6 - Hacking Formulas and Functions
The largest chapter in the book, this section deals with a whole host of useful formulae and functions you can use in your spreadsheets, such as how to display negative time values and hacking vlookup to work over multiple tables.
7 - Macro Hacks
A collection of VBA tips including how to speed up your code, and creating splash screens. This is the weakest part of the book, and I feel VBA should have been left for a seperate book entirely.
8 - Connecting Excel to the World
A small collection of hacks based on data transfer to and from Excel, including XML. The XML tips are only applicable to windows Excel 2003 and later.

As mentioned earlier I have had this book for about a year and I still find myself referring to it for some more advanced uses. If you use Excel regularly, particularly if you use it for analysing data or producing reports, this book is an absolute *must have* for your desktop library!