One of the things I look for when I'm researching a topic is primary sources. Digging back the years using the library for inter-library loan. I was able to get books of collected or annotated primary sources. The last 10 years or so, there has been a push for not only organizations, but individuals to digitize sources and get them online for all to read. Sometimes it's a passion projects (like one I came across for stamps) and for institutions it goes all the way to the Library of Congress.
The goal is to get these sources into the hands of those that need, or indeed, just want to read them. There are a few nuts like me who just like to read the letters or works of the past without a real reason at the time.
Today I want to introduce you to Project Gutenburg. As of right now the site contains over 60,000 free ebooks to be read. The mission statement of the organization as written in 2004, "is to encourage the creation and distribution of eBooks." The have several very handy drop down menus that help you to understand, find, and enjoy the fruits of the labors of volunteers since 1971.