Asimov always had an interest in writing specifically for young adults, even though many of his books for adults were favorites for young readers. He wrote several books for young adults during the 1950's, most of them part of the David Starr series (1952; see separate entry for David Starr, Space Ranger, Vol. 4). The Ugly Little Boy is probably the richest, most emotionally vibrant of his writings for young people during this period.