. . . "Sourcery is the fifth Discworld novel by Terry Pratchett, published in 1988. On the Discworld, sourcerers \u2013 wizards who are sources of magic, and thus immensely more powerful than normal wizards \u2013 were the main cause of the great mage wars that left areas of the disc uninhabitable. As eight is a powerful magical number on Discworld, men born as the eighth son of an eighth son are commonly wizards."@en . . . "Sourcery"@en . . . "0-575-04217-6" . . . . "1988-05-26Z"^^ .