His editions of works originally written for guitar include newly fingered and occasionally revised versions of works from the standard repertoire (most famously, his edition of a selection of twenty "estudios" by Fernando Sor, the "cornerstone" of every serious student's technique since its publication in 1945, although somewhat ironically Segovia in the preface to that work disparaged Sor as "not among the vigorous talents") as well as compositions written for him, including by Heitor Villa-Lobos, Federico Mompou, and Mario Castelnuovo-Tedesco. Many of the latter were edited by Segovia, working in collaboration with the composer, before they were first published. Because of Segovia's predilection for altering the musical content of his editions to reflect his interpretive preferences, many of today's guitarists prefer to examine the original manuscripts, or newer publications based on the original manuscripts to compare them with Segovia's published versions, so as to accept or reject Segovia's editorial decisions.