The Blurb (from Goodreads):
Mystery novelist Harriet Vane knew all about poisons, and when her former lover died in the manner prescribed in one of her books, a jury of her peers had a hangman's noose in mind. But Lord Peter Wimsey was determined to find her innocent.
This is the sixth book in Dorothy L. Sayers’s series of Golden Age murder mysteries featuring the aristocrat-turned-private-detective Lord Peter Wimsey, and the one where the series really begins to turn into something special. All of Sayers’s mysteries are clever, but this one is a little more substantial than the earlier books, with a lot more heart. To begin with, Lord Peter and his clever valet Bunter seemed like a caricature of Bertie Wooster and his valet Jeeves (the comedic creations of P G. Wodehouse), though the occasional flare-up of “shell shock” gave Lord Peter a little more gravitas. By Book 6, Lord Peter is less of a fool and a fop, and more of a clever young man who hides himself behind a constant stream of light-hearted banter.
Strong Poison is truly electrified, however, by the introduction of the character of Harriet Vane, a strong-minded young crime novelist who finds herself on trial for the murder of her ex-lover. Lord Peter has fallen in love with Harriet, but she is determined not to return his regard and resists his charms valiantly. This dash of sexual tension (cunningly concealed as romantic longings) adds both a greater degree of suspense to the puzzle, and humanises Lord Peter, making him much more likeable. A true crime classic.
You might also like to read my review of Clouds of Witness by Dorothy L. Sayers: