Although Judith Merril is best known for her short fiction and her novels (in collaboration with C. M. Kornbluth), she wrote a great deal of nonfiction. She wrote about SF fandom. She wrote about space and space exploration. And she wrote about science fiction. This volume collects Merril's nonfiction from The Magazine of Fantasy and Science Fiction, Extrapolation, and her Year s Best anthologies. In these collected pieces, Merril works through and develops her definition of S-F and what makes S-F good. She chronicles changes within the genre, including the emergence of the New Wave. And she provides a history of the genre: its writers, its publishers, and its magazines.<br><br>Decades ago, Samuel R. Delany declared that Merril...is perhaps the most important intra-genre critic the field has had and...the absence of any of her critical work in book form, in a field aspiring to take itself seriously, is preposterous.... [O]ne cannot know the history of science fiction from 1956 to 1969 if one has not read the brilliant commentary that runs through Merril's best-of-the-year anthologies for that period --from Samuel R. Delany, Starboard Wine.<br><br>Now, in 2016, Aqueduct brings Judith Merril and her place in that history to today s readers.