Unfortunately it's not very interesting.
Dr. Martin H. Greenberg (1941-2011) was the most prolific anthologist and book packager in the world. During his nearly 40-year career in publishing, he created 1,310 anthologies (including 199 single author collections) and more than 950 novels, along with 228 nonfiction books, for a total of almost 2,500 published works. During this time, he commissioned more than 8,350 original short stories and reprinted more than 13,300 short stories (including 807 novels).This is a list of all of the books he edited, including ebooks, and it will be useful to people who find this sort of thing useful. The authorship attribution is a bit puzzling; there is a short introduction by John Helfers, but no indication that he assembled the rest of the material (indeed he is explicitly given copyright only for the introduction); the very short biographical sketch from which I quote above is listed in the contents page as "Commentary by Martin H. Greenberg" but clearly isn't, as it refers to him in the past tense and is cast in the first person plural, without ever saying who "we" are. I read the three pages of introductory material, but it would be an exaggeration to say that I even skimmed the rest.