When Vance is sent a letter claiming something terrible is going to happen to a family that has too much money and too little sense, he witnesses the man get poisoned.
Instead of a complicated locked room mystery, we get a time alibi novel. Not bad with some then current facts about the state of science on poisons and on heavy water are interesting.
S. S. Van Dine is the pseudonym used by American art critic Willard Huntington Wright (October 15, 1888 – April 11, 1939) when he wrote detective novels. Wright was an important figure in avant-garde cultural circles in pre-WWI New York, and under the pseudonym (which he originally used to conceal his identity) he created the once immensely popular fictional detective Philo Vance, a sleuth and aesthete who first appeared in books in the 1920s, then in movies and on the radio.