The EEBO (Early English Books Online) collection is an amazing collection of primary sources. It contains digital facsimile page images of nearly 100,000 books in English printed between 1473 and 1700 - virtually every work printed in England, Ireland, Scotland, Wales and British North America, plus works in English printed elsewhere.
In addition to EEBO, the library has many printed facsimiles. Each of the series listed below includes many books. You can see the contents and locations for any of these titles by searching MnPALS using the series name as a title.