VATICAN CITY -- A new book by Pope Benedict XVI arriving in American stores Tuesday is already an international bestseller.

Jesus of Nazareth has sold more than 1 million copies since it was released in Italian, German and Polish versions last month. The book will eventually be published in 20 languages.

Jesus of Nazareth is the first book by the pope, who had published several books as Cardinal Joseph Ratzinger before his election as pope two years ago.

A study of the life of Jesus from his baptism in the Jordan River to his Transfiguration on Mount Tabor, the 400-page book is based on Old and New Testament Scripture, with a special emphasis on the Gospels of Matthew, Mark, Luke and John.

Despite its biblical grounding, the book includes notable references to non-Scriptural and even non-Christian sources.

An analysis of the parable of the Good Samaritan invokes Karl Marx's concept of alienation; a chapter about the Sermon on the Mount includes the work of Rabbi Jacob Neusner, an American biblical scholar.