In reply to Big Ger:
While none of his books are ones that I re-read a lot, they are mostly enjoyable, covering a wide range. The best for me is "Trillion Year Spree", a very well-informed survey of SF.
Worth it for the title alone: "Bury My Heart at W H Smith's", an autobiographical book.
"Drowning the Ocelot", an article about an encounter with Salvador Dali, also sticks in my mind.