Trent's Last Case, by E. C. Bentley (PB, originally published in 1930, $1)
"One of the best detective stories ever written"- Agatha Christie
When Bentley wrote this mystery, detective stories had become dull, vulgar and poorly written, with their heroes always correct in their deductions. Bentley, according to legend, wrote this book on a wager, to write a story where the detective is human, and not always right. The murder victim, as well, is memorable, really memorable.
This piece of literary history can be found in the mystery section.
