Detection by rule of Thumm. Brooding over the quiet countryside of Tilden County in upstate New York stand the grim walls of Algonquin Prison. And on the very day that Senator Fawcett, a man with many enemies, is found stabbed to death in his study, a little man is released from that prison. Inspector Thumm and his daughter Patience, who have accepted a commission from Elihu Clay to look into the affairs of his "silent partner," try to unravel the web of circumstantial evidence that has enmeshed an innocent man. But time grows short, and John Hume, the District Attorney and the Senator's political opponent, finds a quick conviction expedient. Patience refuses to be beaten by a lack of evidence, and with the help of her father's old friend, Drury Lane, finally stops an execution and brings the true criminal to justice

She wanted to scream but she didn't. She just starred in fascinated horror at the second murdered man she had seen in her life. What she saw was a man lying with cold, dead eyes staring wide at the ceiling, while from the chest jutted the handle of a knife.The senator lay before her with the knife buried up to the hilt in his still warm body. This was a murder with national repurcussions. He had hundreds of political enemies. Any one of them could be the murderer. Drury Lane, the brilliant criminologist, had to come up with a lead in a tangle of faulty clues. Patty, a luscious, wandering blonde with melting blue eyes was on his side- and she was a very necessary aide in one of the most startling mysteries.
How this clever young girl, who sickened at the sight of blood, aided famous Drury Lane in solving a baffling murder with scandalous overtones makes the Tragedy of Z an excitingly different Ellery Queen Mystery.

The first of the two Drury Lane novels which lean rather heavily on Inspector Thumm's daughter, Patience. 
" 'The Tragedy of Z' (1933) is the most impressive of the Drury Lane novels. Its great glory is the finale, where the detective moves through great chains of evidence to deduce the killer. One would hope there would be more finales like this in detective fiction, where logical deduction reigns supreme; but unfortunately it has all too infrequently been taken as a model.  Of all mystery writers, Ellery Queen is the one most interested in reason. Logical deduction is the very essence of the Queen universe." (Michael E.Grost)