The Edward Tufte books are well known classics now, but I distinctly remember my first encounter with The Visual Display of Quantitative Information in 1995. At the time I was working for a market research company in Denver. I noticed the book sitting on the president's desk while I was in his office doing some typical small business IT stuff. I had never heard of it, and I was intrigued. I started casually paging through it-- and I was absolutely enthralled. I couldn't put it down. After Karl arrived, I told him how amazing the book was; I had to have my own copy. He expressed some surprise that he had no luck getting his market analysts to look at the book, but his crazy IT guy just happened to see it in passing and treated it like some new kind of religion.
This is a companion discussion topic for the original blog entry at: http://www.codinghorror.com/blog/2005/04/because-information-is-beautiful.html