C.S. Lewis: A Biography.
A.N. Wilson.
1st Paperback Edition 1991.
Flamingo.
ISBN 0006544282.
Paperback.
Hammond p.388.

At least 6 impressions issued.

Includes various Lewis-related remarks by Tolkien, taken from manuscript notes in books from his library.

Also includes extracts from letters previously published in The Letters of J.R.R Tolkien (1981).

Early impressions had 'C.S. LEWIS' blocked in gold foil, whereas for later impressions the name was printed in orange.  This happened no later than the 6th impression.