The ISBN of The Code Book is 978-1857028799.
The DOI (Digital Object Identifier) is a unique alphanumeric code assigned to a specific publication, while the ISBN (International Standard Book Number) is a unique numeric code assigned to a book.
The ISBN (International Standard Book Number) is located near the bar code and on the reverse of the title page; it will be a series of numbers (how many numbers depends on the book's age) preceded by "ISBN". The ISBN was introduced in 1966, so books printed before then will not have one.
The ISBN of The Code of Romulus is 9781842555804.
The ISBN of The Code of the Woosters is 1841591009.
On the back cover, usually on or near the bar code.
The ISBN of Code of the Clans is 978-0061660092.
The ISBN of The AdSense Code is 978-1933596709.
The ISBN of The Phish Book is 0375502033.
The ISBN of The Book of Renfield is 0743243544.
The ISBN of Asta's Book is 0140176616.
The ISBN of The Graveyard Book is 0060530928.
The ISBN of Book of Haikus is 9780142002643.