There's a good Washington Monthly article on Edward Tufte, whose books I adore. Anybody responsible for conveying information to the public should read both the article and Tufte's books. The classic is The Visual Display of Quantitative Information, but I also recommend Beautiful Evidence. The poster Tufte sells of Napoleon's march on Moscow, and subsequent retreat, by Charles Joseph Minard, hangs on my living room wall.

The article says:

“His four books on the subject [data visualization] have sold almost two million copies, and
in his crusade against euphemism and gloss, he casts a shadow over the
world of graphs and charts similar to the specter of George Orwell over
essay and argument.”

The field has lately been growing by leaps and bounds. I also love Howard Wainer's books on the subject, such as Picturing the Uncertain World  – he places more emphasis on the statistical validity behind the presentation of data in visual form. But there are now lots of websites. I like Infosthetics. And recently came across C.A.Hidalgo (thanks to Tim Harford's excellent new book Adapt). Other suggestions will be most welcome!