Not just 100 books, not even the top 10, but 1000 novels! The Guardian ran this in 2009, so many a couple more books since published might make the list some day. Grouped by genres rather than author, there are many repeat authors, and many omissions. Not a single Jack Vance novel, nothing by Tim Powers, James Blaylock, one of Robert Heinlein’s worst books makes the list and no other novels of his. As far as Terry Pratchett, rather than list one or two of five books (like Muriel Spark), they are grouped under “Discworld series” which has over 30 books. Nice cop-out, Guardian. Like any list, I suppose. Definitive is a subjective term.