Not to Be Taken — Anthony Berkeley

"The murder is by arsenic; and although the number of suspects is strictly limited the construction is so ingenious that to attain the correct solution of the problem requires all the reader's concentration; to skip is fatal." Times Literary Supplement, 1938

John Waterhouse has died of some gastric complication. Exhumed at his brother's request, it transpires that he has been killed by arsenical poisoning, though nobody in the sleepy village of Anneypenny seems to have had a reason to do him ill. Rumors abound of Nazi intrigue and military skullduggery, but whatever the motive, the truth remains; this was murder.

Originally serialized as a competition with a prize for the readers that could answer Berkeley's direct challenge of 'who was the poisoner?', Not to Be Taken remains one of the most fiendish exercises in subtle clue work and detection from the Golden Age of Crime.