in summarizing the findings of a forthcoming monograph and edition, this article reviews the forces leading to the major revisions of chant characteristic of the period 1590–1890. it identifies the major independent editions, outlines their chief characteristics, and documents the need for a geography of chant practice during these centuries. the fundamental changes wrought by the several editors brought about an individualization in melodic constructions and undoubtedly caused accompanying differences in learning processes. new comparative transcriptions of the alleluia veni domine provide a view of representative editorial processes.