Alexander's novel "The Marvelous Misadventures of Sebastian" (1970) was rejected after its first submission, and Alexander rewrote it three times before it was published. It won the National Book Award in 1971. He published two picture books: "The King's Fountain" (1971) for which he collaborated with the author Ezra Jack Keats, and "The Four Donkeys" (1972). He wrote the novel "The Cat Who Wished to be a Man" in 1973. The same year Alexander published "The Foundling: And Other Tales of Prydain", a companion book to the Prydain series. After the success of "Prydain", Alexander was author-in-residence at Temple University from 1970 to 1974. He once described it as being educational for him and as "rather like being a visiting uncle, who has a marvelous time with his nephews and nieces, then goes off leaving the parents to cope with attacks of whooping cough, mending socks and blackmailing the kids to straighten up the mess in their rooms." Alexander wrote "The Wizard in the Tree" while suffering from depression and published it in 1975. The character Arbican was based on Alexander and his personal struggles. In 1977 Alexander published "The Town Cats", which received a more favorable critical reception than "The Wizard in the Tree". His next book "The First Two Lives of Lukas-Kasha", set in a fantasy world based on 15th century Persia, was published in 1978. It won the Silver Slate Pencil Award in Holland and the Austrian Book Award in Austria.