"New sources for Shakespeare do not turn up every day... This is a truly significant one that has not heretofore been studied or published. The list of passages now traced back to this source is impressive." - David Bevington, Professor Emeritus, University of Chicago "A Brief Discourse of Rebellion and Rebels" is the only uniquely existent, unpublished manuscript that can be shown to have been a source for Shakespeare's plays. George North wrote the treatise in 1576 while at Kirtling Hall, the North family estate in Cambridgeshire. His manuscript, newly uncovered by the authors at the British Library, has many implications for our understanding of Shakespeare's plays. for example, not only does it bring clarity to the Fool's mysterious reference to Merlin in King Lear, but also upsets the prevailing opinion that Shakespeare invented the final hours of Jack Cade in 2 Henry VI. Linguistic and thematic correspondences between the North manuscript and Shakespeare's plays make it clear that the playwright borrowed from this document in other plays as well, including Richard III, 3 Henry VI, Henry V, King John, Macbeth, and Coriolanus. The opening chapters of the book investigate such connections; the volume also contains both a transcript and a facsimile of "A Brief Discourse", making this previously unknown document readily available. DENNIS MCCARTHY is an independent scholar; JUNE SCHLUETER is Charles A. Dana Professor Emerita of English at Lafayette College, Easton, Pennsylvania.