For Adults:
The Unheard Music (1950)
The Mushroom Planet Series:
The Wonderful Flight to the Mushroom Planet (1954)
Stowaway to the Mushroom Planet (1956)
Mr. Bass's Planetoid (1958)
A Mystery for Mr. Bass (1960)
Jewels from the Moon and The Meteor that Couldn't Stay (1964)
Time and Mr. Bass (1967)
The Julia Series:
A Room Made of Windows (1971)
Julia and the Hand of God (1977)
That Julia Redfern (1982)
Julia's Magic (1984)
The Private Worlds of Julia Redfern (1988)
Other Books for Children:
The Terrible Churnadryne (1959)
The Mysterious Christmas Shell (1961)
The Beast with the Magical Horn (1963)
A Spell is Cast (1964)
The Court of the Stone Children (1973)
To the Green Mountains (1975)
Beyond Silence (1980)
Essay Collections:
The Green and Burning Tree (1969)
The Seed and the Vision (1993)