Little Blue and Little Yellow.  Astor-Honor, New York, 1959, renewed 1987

** Inch by Inch.  Astor-Honor, New York, 1960, renewed 1988   

On My Beach There Are Many Pebbles.  Astor-Honor, New York,1961, renewed 1989

** Swimmy.   Knopf, New York, 1963, renewed 1991

Tico and the Golden Wings.  Pantheon, New York, 1964, renewed 1992

** Frederick.   Pantheon, New York, 1967, renewed 1995 

The Biggest House In The World.  Knopf, New York, 1968, renewed 1996       

The Alphabet Tree.  Pantheon, New York, 1968, renewed 1996 

** Alexander and the Wind Up Mouse.  Pantheon, New York, 1969, renewed 1997 

Fish is Fish.  Pantheon, New York, 1970, renewed 1998          

Theodore and the Talking Mushroom.  Pantheon, New York, 1971, renewed 1998

The Greentail Mouse.   Pantheon, New York, 1973, renewed 2001

Pezzettino.  Pantheon, New York, 1975, renewed 2004

In the Rabbitgarden.  Pantheon, New York, 1975, renewed January 1, 2004

A Color of His Own.  Pantheon, New York, 1976, renewed 2004 

I Want to Stay Here I Want to Go There:  A Flea Story.  Pantheon, New York, 1977

Parallel Botany.  Knopf, New York, 1977

Geraldine The Music Mouse. Pantheon, New York, 1979

Mouse Days.  Pantheon, New York, 1979

Let's Make Rabbits.  Knopf, New York, 1982

Let's Play. Random House, New York, 1983,

Cornelius.  Pantheon, New York, 1983                    

Who  Pantheon, New York, 1983

What  Pantheon, New York, 1983

When  Pantheon, New York, 1983

Where   Pantheon, New York, 1983

Frederick’s Fables: A Leo Lionni Treasury. intro by Bruno Bettelheim, Knopf, New York, 1985

Colors Pantheon, New York, 1985

Letters Pantheon, New York, 1985

Numbers Pantheon, New York, 1985

Words Pantheon, New York, 1985

It's Mine  Knopf, New York, 1985

Nicholas Where Have You Been.  Knopf, New York, 1987

Six Crows. Knopf, New York, 1988

Tillie and The Wall.  Knopf, New York, 1989

Matthew's Dream.  Knopf, New York, 1991

A Busy Year. Knopf, New York, 1992

Mr. McMouse.  Knopf, New York, 1992 

An Extraordinary Egg. Knopf, New York, 1994                   

Between Worlds.  Autobiography, Knopf, New York, 1997

​

** Winner of Caldecott Honor Award