The Great SF Series: Science Fiction on the Grand Scale

These are the epics of Science Fiction - 102 of the best series writing in the genre. Some are multi-volume sagas and/or story arcs involving recurring characters; others are stand-alone works that inhabit the same fictional universes as their companion volumes. Some of them are classics; some of them are pulp schlock that have transcended their origins. All of them are well worth reading. I have limited the list to Series by individual authors(or collaborators) specifically conceived as written fiction; there are no movie/tv tie-ins, and no continuations by other writers. I have excluded traditional fantasy; Tolkien et al deserve a list of their own ( The Zelazny and Vance are hybrids with enough SF elements to qualify; the Earthsea cycle is unique unto itself). In order to keep the list manageable, I have sometimes resorted to using a single entry to represent an entire series, while at others I've listed individual works. In the former case, partial credit counts!