Malory's Morte Darthursurvives in two versions: the Winchester manuscript, which has been dated 1469-70, and the edition Caxton published in 1485. These versions were thought to be collaterally related through a common source to an original lost manuscript, until in 1977 new evidence suggested a linear descent. Dr Tieken-Boon van Ostade's study supports this argument, first through a detailed refutation of Vinaver's arguments for collateral descent, then through an analysis of the incidence of multiple negation in both versions of the Morte Darthurand the conclusions to be drawn from it. A reconstruction of the events leading to Caxton's publication of the text at a politically hazardous time completes the volume.Dr INGRID TIEKEN-BOON VAN OSTADEis lecturer in English at the University of Leiden. Two books already published centre on the history of the English language.