Show Me The Numbers
Stephen Few should be required reading for anybody who inflicts Excel graphs and PowerPoint presentations on an unsuspecting public. Everybody knows how to use those applications, very few know how to use them right. As a result, people take away the wrong message, or have absolutely no idea what the purpose of the slide show was.

Few explains design in terms of communicating information.

A must have book for presenting data
I had to buy more than one because so many people borrowed my copy. It is essential to read if you do a lot of presentations of critical material.

demystify the cloud
if you have to present or report complex information to others, this and tufte's other tomes are a very useful and are good reference library books.

Superb analytical writing
Tufte is a master of laying out the problem, revealing misguided analysis used in the two studies that he dissects and then shows how to better interpret the data. I found myself slowing down my usual reading speed to half and doubling my concentration to follow him, which is a compliment to the depth of his writing. Tufte is concise and a well-regarded authority on the methods to describe, define, reveal and present problems so that solutions are found honestly. I recommend reading all his work.

Visual and Statistical Thinking....very visual
A very good book on a fairly obscure but very important subject. Being able to effectively communicate numerical/statistical information in a graphical way is far more art and aethetics, than science. Anyone who uses charts and graphs to convey important information should get this book. In other works by Tufte, he shows how proper use of explaining critical numerical information could have stopped the Space Shuttle from launching on a cold morning which eventually led to it exploding shortly after tackoff in 1987 - due to an o-ring failing to seal properly. A fascinating read that reveals how important graphs are to making sense of numerical data.