Strong Poison

Strong Poison was published in 1930 and is one of the most important books in the Sayers canon, not because the puzzle is her best but because it introduces Harriet Vane. The setup is unforgettable. Harriet Vane, a young mystery novelist who lived for several years with a writer named Philip Boyes, is on trial for his murder by arsenic poisoning. The evidence against her is overwhelming. Peter, who has never met her, sees her in the dock and falls in love.

The rest of the book is essentially Peter’s race against the second jury panel (the first trial ended in a hung jury) to find the actual killer. The investigation involves the unusual properties of arsenic, the wills and inheritance of a deceased lawyer, and the social structure of a small literary set in 1920s London. Miss Climpson is dispatched undercover to a sleepy provincial town to get the evidence Peter needs. The eventual solution is clever rather than profound. The real importance of the book is what it sets up. Harriet Vane will refuse Peter’s proposals across the next several novels before finally accepting him in Gaudy Night.