One of the unique things about the Modern Library Series, were the collection of authors and scholars who wrote the introductions for many of the titles, sometimes include a special introduction written by the book's owner author.
For some collectors, completing a collection will include the books for which their preferred author wrote a preface or introduction.
This list is alphabetical by Preface or Introduction author.
Conrad Aiken - Twentieth Centry American Poetry (Anthology) - ML 97.2
Brooks Atikinson - New Voices in the American Theatre (Anthology) - ML 258.3
Carlos Baker (Princeton University) - The Selected Poetry and Prose of Shelley - ML 274.1
Ruby Cohn (San Francisco State College) Four Contemporary French Plays - ML 90.3