Obelists Fly High

A surgeon is murdered in mid-air with only his fellow airplane passengers as possible suspects in this classic closed circle mystery set in the age of early aviation.
1935: A surgeon, the appropriately named Dr. Cutter, is preparing to fly cross-country in a two-propeller plane to perform a life-and-death surgery on his brother, the Secretary of State. Just before boarding, he receives an anonymous note that says, You will die April 13th at Noon exactly Central Time. It seems to be an absurd threat because he is scheduled to be in mid-air in the company of a small number of passengers at that hour.
Of course, he is murdered and the only suspects are in a confined area, all swearing that they saw nothing. This is the conundrum facing NYPD Detective Michael Lord before he, too, is threatened. Fortunately, he is accompanied by his friend, Dr. Rees Pons, who attempts to aid him by calling on his knowledge and experience as a psychologist.
As one of the most creative writers of impossible Golden Age detective stories, King incongruously begins with an epilogue, concludes with a prologue, and even provides a "Clue Finder" that reveals all the hints that would have helped the astute reader solve the crime that could not possibly have been perpetrated.

C. Daly King (1895-1963) was an American psychologist and detective story writer. He was born in New York City and educated at Yale University. After fighting in World War I, he worked in textiles and in advertising before returning to school to study psychology, with a particular focus on sleep and consciousness. In the 1930s, King published nine books that quickly established him as a master of the Golden Age mystery, but ceased writing fiction with the advent of World War II.
Otto Penzler, the creator of American Mystery Classics, is also the founder of The Mysterious Press (1975); MysteriousPress.com (2011), an electronic-book publishing company; and New York City’s Mysterious Bookshop (1979). He has won a Raven, the Ellery Queen Award, two Edgars (for the Encyclopedia of Mystery and Detection, 1977, and The Lineup, 2010), and lifetime achievement awards from NoirCon and The Strand Magazine. He has edited more than 80 anthologies and written extensively about mystery fiction.