Harry J. Schaare

Title: Doctor on Test
Author: Kerry Mitchell
Publisher: Dell (#2009)
Published: December 1965, ©1963
Illustrator: Harry J. Schaare

He is credited on the back cover.

Keeping jet test pilots in top physical condition should have been easy for an experienced doctor like Bennet Grady—but coping with a headstrong lady psychiatrist, while balancing a dangerous romantic triangle at the same time, made it almost impossible ... until he decided to learn a few ground rules for love.