A ghostwriter is an author who writes under someone else's name, with their consent. A ghostwriten book is thus somewhat deceptive- the author on the cover is not the actual writer.
Ghostwriters are often employed by celebrities to write autobiographies in situations in which the celebrities themselves may not be talented authors.
... up it to Albany, discovered Hudson Bay
Alexander von Humboldt, (1769-1859), explored Central and South America, visited Siberia
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Helge Ingstad, (1899-2001), Norwegian, ...