“On this site the University of Chicago Press is pleased to present the first three volumes of the History of Cartography in PDF format. Navigate to the PDFs from the left column. Each chapter of each book is a single PDF. The search box on the left allows searching across the content of all the PDFs that make up the first six books.”

http://www.press.uchicago.edu/books/HOC/index.html

( via Hacker News: https://news.ycombinator.com/item?id=12116231 )