Erle Gardner - Turn on the Heat

The day she told her husband he could go his own way, were it blonde or brunette, she became a happy woman. Freed from the duty of preserving a contour that would keep Mr. Cool home nights, she gave up dieting, and serenely watched her figure expand to balloon-like proportions.
Inside, she was hard as nails, shrewd and unscrupulous, stingy, avaricious. She handled cases no decent agency would touch. She hired Donald Lam for two reasons he hod brains, and she knew he needed a job so badly that she could get him for practically nothing. She watched his expense account like a vulture and did her best to deduct legitimate expenses from his already meager salary.
But deep inside that mountain of flesh must have been a heart, for in spite of these instincts she developed an affectionate, almost solicitous, loyalty for Donald.
You’ll like Bertha Cool. She is lusty and gusty and has personality.
Every runt gets pushed around Donald Lam was no exception. The difference between him and most runts was that the harder you pushed the faster Donald came back. He discovered early in life that his hands weren’t much use to him in a fight, so he used his head. And there was nothing soft about Donald’s head. He used his mind and trained it mercilessly. Sometimes it got him into trouble because he was just a little too far ahead of the other fellow.
Nor was Donald too ethical. He’d learned that if nature had made you pint size, it was easier to trip a man up than knock him down. Some people called Donald “poison.”
There was only one thing about him that worried Bertha Cool. She thought he was too susceptible to women. Maybe he was. There was no doubt that women made fools of themselves over Donald. Bertha didn’t understand why but she didn’t mind. Donald’s girlfriends were pretty useful.