The Long Secret

The Long Secret
First edition
AuthorLouise Fitzhugh
IllustratorLouise Fitzhugh
SeriesHarriet the Spy
GenreChildren's spy novel
PublishedOctober 27, 1965
PublisherHarper & Row
Publication placeUnited States
Media typePrint
Pages275 (first ed.)
ISBN0060214104
OCLC70458678
LC ClassPZ7.F5768 Lo
Preceded byHarriet the Spy 
Followed bySport 

The Long Secret is a children's novel written and illustrated by Louise Fitzhugh that was released by Harper & Row on October 27, 1965. It is a sequel or "companion" to Harriet the Spy (1964), the only one published during Fitzhugh's lifetime.

Sport, another sequel to Harriet written by Fitzhugh, was published by the Dell imprint Delacorte Press in 1979.