By 1990, Auel's first three books in her Earth's Children series had sold more than 20 million copies worldwide and been translated into 18 languages; Crown Publishers paid Auel about $25 million for the rights to publish The Plains of Passage and the two subsequent volumes.
En 1990, os primeiros tres libros de Auel da saga Os fillos da terra venderon máis de 20 millóns de copias e foron traducidos a 18 linguas; Crown Publishers declarou ter pagado a Auel preto de 25 millóns de dólares polos dereitos para publicar The Plains of Passage e os dous volumes seguintes.