What is the author's style in Waldo by Robert A. Heinlein?

Heinlein begins and ends "Waldo" with a glimpse of an older, more mature Waldo than is seen in the rest of the story. This is a Waldo who is both physically and intellectually fit, he is both a body and a brain (a dancer and a brain surgeon). When a reporter asks Waldo how he got started in dance, the story flashes back to Dr. Stevens and the problems at North American Power-Air with the non-functioning deKalb receptors. The rest of the story unfolds in a straightforward chronological pattern explaining how Waldo solves both the problems of the balky deKalbs and the radiant power that is weakening humankind. At the end of the story, Heinlein closes his frame by returning to the older, physically fit Waldo in order to emphasize the fitness (and politeness) of Waldo now that he has become a whole person in mind and body.