Sir John Fielding, co-founder with his late half-brother Henry (author of Tom Jones) of the Bow Street Runners, has been dead for 200 years, but he's just now getting his first starring role in a detective story. Here, in 1768, the blind magistrate rescues orphaned printer's apprentice Jeremy Proctor from a trumped-up robbery charge just in time to take Jeremy along as his youthful Watson while he investigates the apparent suicide of Lord Richard Goodhope, shot inside a locked library. Surprises abound, even for the seasoned Sir John: Lord Goodhope, who was on distant terms with his wife, died of poison, not his gunshot; the library is not quite so hermetically sealed as it appears; notorious gambler Black Jack Bilbo claims to hold Goodhope's markers for ú12,000; one of his footmen left Goodhope's employ very recently, only to turn up in quite another connection. Even Mary Deemey, the invincibly English dressmaker who supplied widow's weeds to Goodhope's current actress companion, is masquerading as one Mlle. Claudette. But though he constantly has to ask Jeremy to describe things and places and people for him, nothing fools Sir John, and his clever identification of a suspect sets the stage for an old-fashioned denouement in the Goodhope library. Pseudonymous Alexander's debut wraps a competent mystery in a historical narrative of vivacity and charm. The final paragraph promises a sequel, perhaps a series.