Colin Wilson was an important writer in my (ahem) intellectual development. Essentially, he was an existentialist philosopher who worked across a wide range of genres.
Although since I became a Christian I have not found him so useful, up till then he was someone who I would return to. I published a few essays in a home-produced little journal called Abraxas, edited from Cornwall by a certain Paul Newman (neighbour and friend to CW) , and dedicated to Wilson and his interests.
Colin Wilson wrote a LOT of books (which is necessary if you are a professional writer, want a decent income, and when you are not a bestselling writer).
The first place I came across him was his introduction to William Arkle's Geography of Consciousness (Bill Arkle had been a neighbour of mine, 'tho I didn't know him. He lived on Backwell Hill in Somerset, near where my sister kept her pony). This I read in the summer of 1978 in a copy from Edinburgh City Library.
These are some of my favourite of Wilson's books.
The Outsider, 1956
Adrift in Soho, 1961
Bernard Shaw, 1969.
Introduction to the New Existentialism, 1966
Voyage to a Beginning (autobiography), 1969
Tree by Tolkien, 1973
The Craft of the Novel, 1975
Lord of the Underworld (about Jung), 1984
The Essential Colin Wilson, 1985
Spider World series of Sci Fi novels, starting 1987
The Books in my Life, 1998
Dreaming to some Purpose (autobiography), 2004