If you, like I, have read an awful lot of books, a real treasure is one in which you aren't sure what is going on, have no idea where it's going, grabs your attention and interest from multiple directions (many times simultaneously) and will not allow you to stop reading.
Fowles has been consistent in offering such gems, though some works more successful than others. "Mantissa" (the term refers to the numbers to the left portion of the decimal point in a logarithm - from the Greek for the lesser part of a phenomena) is barely 192 pages long. Miles Green and his Muse, Erato, are in a continual sturgle for recognition, sexual gratification, intellectual combat, and deep, deep, treacherous love. I found myself stopping startled in my reading, recognizing the words and gestures described of Erato's behavior as identical to relations I've experienced.
Erato is the actual Greek Muse - a minor divinity who inspires Aristophenes,Shakespeare, Homer, Virgil, T.S.Eliot and countless others to the hieghts of their creative powers.
Or so she says.
The book is gossipy about the greatest authors of all time - they are dismissed the way your current lover describes old, failed loves.
I suggest you read this at one sitting. it's *very* erotic, but there only as prelude and coda to the conflict.
It's the heartwarning story of a man and his Muse. For men and women of all intrests.