Gray Timothy:

One of the prolific author's many crime novels, Edgar Wallace's Grey Timothy (a.k.a. Pallard the Punter) follows the adventures of professional horse racer Brian Pallard as he ingratiates himself into the family of his stuffy businessman uncle Peter Callander (as well as into the heart of his second cousin Gladys) while sparring with his crooked rival Lord Pinlow.

The story is straightforward, with Pallard slowly winning over the Callanders whose first impression of him is that of a degenerate gambler, slowly charming Gladys into courtship, and outsmarting Pinlow at one scheme after another by either being one step ahead of his schemes or being fortunately lucky at the right moment. The pacing is good, the twists and reveals are mostly plausible, and the characters are even nuanced enough for the reader to care about what happens. There's plenty of technical racetrack talk, and numerous asides exploring the hypocrisy of businessmen involved in market speculation (a.k.a. gambling) looking down their noses at other forms of gambling and competition as sinful and degenerate.

I'm not as much of a fan of Wallace's science fiction or "Africa Adventure" novels, but his crime novel output for the time period is solid and entertaining, and Pallard the Punter is no exception.