There were 38 titles in the original Judy Bolton series, all copyrighted between 1932 and 1967. The final 12, particularly the last one, had limited printings and as a result are hard to find. Collectors often find themselves paying upwards of $200 for a volume in good condition. The series ended before the 39th book, "The Strange Likeness", could be published. According to author Margaret Sutton, the series was killed due not to poor sales, but to pressure from the Stratemeyer Syndicate. The Stratemeyer Syndicate wished to lessen competition for the Nancy Drew series. Pelagie Doane illustrated many of the early Judy Bolton books.