Rossell Hope Robbins collaborated with Carleton Brown in the publishing of the Index of Middle English Verse in 1943. With John L. Cutler, associate professor of English in the University of Kentucky, he has now compiled a supplement to the Index incorporating those texts published since 1943. At the same time, the two have completely revised the Index by including in the Supplement texts previously neglected. The number of entries has been increased to 6,000, and more than half of the 4,500 original entries have been revised. 
In addition to this basic revision, the appendices of the Index have been corrected and enlarged, especially the listing and locating of privately held manuscripts. Cross references have been inserted abundantly to facilitate easy use of the combined works. Additionally, reference has been made to related specialized studies.
The large number of new entries is attributable not only to prolonged manuscript research but also to a broadening of the original criteria for the inclusion of poems. Rather than cutting off entries at 1500, which the authors felt impaired the usefulness of the original Index, Robbins and Cutler included genres that had not concluded but continued into the sixteenth century, as well as poems with uncertain dates they felt would be important for scholars. The Supplement overcomes these barriers by including the so-called Scottish Chaucerians, the late fifteenth and early sixteenth century manuscripts such as the "Tudor songbooks," verse items of only two lines, and tombstone and church bras epitaphs.