This puzzle comes from How to Swindle in Chess by Andrew Soltis. My review will be appearing on British Chess News within the next few days.
Black had sacrificed her queen in the game Czerniak – Sonja Graf-Stevenson (Mar del Plata 1942). Black’s last move, Bc6, threatened Rxd3 followed by Ng6+.
White has no immediate defence so does best to play 21. gxh6! f5! 22. exf6! Rxd3! 23. Qxd3 Ng6+ 24. Qxg6 Rxg6 with an endgame edge.
Instead, the game continued 21. Qe2? Rxd3! 22. Qxd3 Ng6+ 23. Qxg6 fxg6! with Rf8 to follow, after which Black eventually won.
Congratulations to Chris Baker on his excellent analysis of this complex position.