This is a very useful book for anyone wanting to go beyond casual use of Excel. The tips range from obvious cell-formatting to fairly sophisticated data integration. For example, I didn't know that you can import data into excel from html tables. There's a nice wizard that displays the web page and lets you select what you want to import. Very cool.
The most interesting thing about this book is the typographic and graphic layout. Very innovative. There are screenshots overlaid with colored and numbered bullets and arrows, with each one described in a concise textual table next to the screenshot. It's a little hard to describe, but it works well, conveys a lot of information, and is visually appealing. I liked it.