Parker Pyne Investigates is a short story collection written by Agatha Christie and first published in the UK by William Collins and Sons in November 1934. Along with The Listerdale Mystery, this collection did not appear under the usual imprint of the Collins Crime Club but instead appeared as part of the Collins Mystery series. It appeared in the US later in the same year published by Dodd, Mead and Company under the title Mr. Parker Pyne, Detective. The UK edition retailed at seven shillings and sixpence (7/6) and the US edition at $2.00.

The Listerdale Mystery is a short story collection written by Agatha Christie and first published in the UK by William Collins and Sons in June 1934. The book retailed at seven shillings and sixpence (7/6). The collection did not appear in the US; however, all of the stories contained within it did appear in other collections only published there.