In the 1950s, de Hartog took
The Rival to Houston, Texas on the deck of a freighter. The book received a national response but also a local response in which, within a week of the book's release, nearly four hundred citizens volunteered at the hospital. In 1967, de Hartog wrote
The Captain, which revisited his love of the sea and featured a central character based loosely on himself called Martinus Harinxma, who had first appeared in
The Lost Sea (1951). The book was a success, and Martinus would live on as a central character in several sequels. Before starting work on the second in the Martinus series, de Hartog wrote of the experience of adopting his two daughters, who were
Korean War orphans, in
The Children, which appeared in 1969. He wrote a fictionalized account of the origin of the Religious Society of Friends,
The Peaceable Kingdom: An American Saga, in 1972. It was nominated for the Nobel Prize and was followed eight years later by a Quaker novel, ''The Lamb's War'' (1980). In 1985, de Hartog was awarded an honorary Doctor of Humane Letters (L.H.D.) degree from
Whittier College. He published the next book in the Martinus series,
The Commodore, in 1986 while he was living in The Walled Garden in
East Coker,
Somerset, England, and it was followed by
The Centurion (1989), which explored an interest in which he and his wife had become involved,
dowsing. In 1993, de Hartog and his wife returned to Houston. He returned to the Quaker theme to write the last in the series,
The Peculiar People, in 1992. In 2007, Marjorie de Hartog edited a short story that her husband had begun,
A View of the Ocean. == Media ==