Shakespeare Quartos Archive
The Shakespeare Quartos Archive is a digital collection of pre-1642 editions of William Shakespeare's plays. A cross-Atlantic collaboration has also produced an interactive interface for the detailed study of these geographically distant quartos, with full functionality for all thirty-two quarto copies of Hamlet held by participating institutions.
For more information, please read the Folgerpedia article Shakespeare Quartos at the Folger.
While the project is no longer in active development, the website that was developed for Hamlet in conjunction with it may be found here: http://www.quartos.org/