 The Introduction was almost certainly written while William was lecturing on logic at the University of Paris. It was first edited by Grabmann (1937) and translated into English by Kretzmann (1966). A new critical edition was produced by Brands and Kann (1995), accompanied by a translation into German. It has been argued (Mullinger 1873, p. 177) that this book was heavily influenced by a Synopsis treatise written by the 11th-century Byzantine logician Michael Constantine Psellus. The Introduction contains the first appearance of the syllogistic mnemonic verse ‘Barbara, Celarent…’, which Augustus de Morgan described as “magic words … more full of meaning than any that ever were made”, and Sherwood may even have been the inventor of the verse, though references to individual names appear earlier (Kretzmann 1966, pp. 66–67).