Clare Lennart was the pen name of Clara Helena van den Boogaard-Klaver, born in the eastern Netherlands to painter Luite Klaver and his wife Gerarda Jacoba Doyer. At age 15, she began training as a teacher at the government training college for girls in Apeldoorn. After graduation, she taught French and English at several schools. In 1926, while teaching in Utrecht, she met her future husband, Wim van den Boogaard, then a married man. She opened a boarding house and began writing books. Her debut novel Adventure was published in 1935. She also also wrote children's stories. In 1939, she moved to Rotterdam to be closer to van den Boogaard, who was stationed there with the army, but after the Nazi bombing of the city in May 1940, she fled back to Utrecht. In 1947, the couple finally married after van den Boogaard's first wife died. Besides her own writing, Clare Lennart also translated English and French works into Dutch, including works by Pearl S. Buck, Truman Capote, Charles Dickens, and Colette.