Early American Imprints is a digital and microopaque card (not the more common microfiche) collection produced by Readex.
Ralph Shaw (1907–72) and Richard Shoemaker's (1907–70) collaborative efforts continued American Bibliography.
[1] American Bibliography contains the full text of all known existing books, pamphlets, and broadsides printed in the United States (or British American colonies prior to Independence) from 1639 through 1819, some 72,000 titles.
It is now also available in electronic form as part of the Readex Archive of Americana.
Many other major libraries in the United States and Europe also made texts available and provided editorial corrections to the original bibliographic work of Charles Evans.