The Wonderful Flight to the Mushroom Planet is a children's science fiction novel written by Eleanor Cameron, illustrated by Robert Henneberger, and published by Little, Brown in 1954.

It is set in Pacific Grove, California, and on Basidium, a tiny habitable moon of Earth, invisible from the planet in its orbit 50,000 miles away.

Using his marvelous stroboscopic polarizing filter he shows the boys a previously undetected satellite of the Earth, which he calls Basidium-X.

He refits their spaceship, giving them some special fuel he invented to power it, and tells them to fly to the mushroom planet (after getting their parents' permission).

They quickly meet some residents of the mushroom planet, small men with large heads and slightly green skin, of the same people as the mysterious Mr. Bass.