THE A.B.C. MURDERS
A HERCULE POIROT MYSTERY (HERCULE POIROT MYSTERIES)
by Agatha Christie
Hercule Poirot comes out of his retirement, enticed to the chase by a series of anonymous letters, each one prophesying a murder in a certain town on a certain date. He fails — for four times — then the net tightens. Mental deduction rather than tangible clues.