The man was heavily influenced by surrealism.
Who'd have thought that a style as offbeat as that could be bent to commercial use?
According to Wikipedia he frequently used only four lights for his studio photography, one of which was directly overhead.
He experimented with still lifes (above) and used the best ideas in his human photography.
He also shot interiors. The text usually suggested that they were pre-existing, real-life rooms but they were often enhanced by Horst's own collection of furniture and accessories.
...and a flare for drama.
Outdoor photography...no problem.
Interesting, eh?