There are some stories in this book I haven’t read. I’m curious to know if any of them have anything to do with this cover. The title story does not.

You may not like The Door Into Summer, but you can’t deny that it has has some amazing covers in the foreign markets:

I can’t get this one to imbed: https://www.reddit.com/r/badscificovers/comments/ntcoqu/doorway_into_summer_by_heinlein_russian_edition/#lightbox

Stranger in a Strange Land

The Heinlein insert doesn’t tell Valentine Michael Smith about homosexuality because he expects that he will “Grak it is great wrongness,”” and yet

Here’s the original magazine cover for Universe, the first part of Orphans of the Sky

https://www.blackgate.com/wp-content/uploads/2021/02/Astounding-Science-Fiction-May-1941.jpg

Good think they updated that character design for more recent publications

https://www.sfgateway.com/titles/robert-a-heinlein/orphans-of-the-sky/9780575113206/