The Riddle of the Third Mile — Colin Dexter

How does an Oxford don spell "irresistible?" What was the venerable gent's pleasure? A glass of whisky with a working girl?

THE RIDDLE OF THE THIRD MILE
The hideously dismembered corpse in the Oxford Canal poses a perplexing riddle for Inspector Morse. Is it that of Professor Browne-Smith, a meticulous Oxford don who vanished, leaving only a carelessly misspelled note? Apparently lured from the ivory towers of Oxford to the fleshpots of Soho by the promise of free love, Browne-Smith expected discreet sexual depravity at no charge. But he may have paid the dearest price.

Chief Inspector Morse, Homicide Division, Oxford: A lonely middle-aged bachelor with a taste for Mozart and T.S. Eliot, pints of bitter--and an obsession with attractive women. As coarse as he is cunning, at times insufferable, relentlessly inquisitive.