Content Directions, the commercial registrar for the Digital Object Identifier (DOI) and a consultant on its use, has entered into an agreement with ibooks, ipicturebooks and Children's E-Library to provide DOIs for all of its publications, a total of more than 1,700 titles. The DOI is a Web-based system for identifying and retrieving a wide variety of supplementary information for books and other intellectual property.

Byron Preiss, CEO of ibooks, said his company was dedicated to using technology to produce and market its books. "The DOI enhances these missions by making it much easier for our customers to find and buy our books," he said.

Preiss emphasized the importance of "global searchability" for the school and library market. "Information can be searchable at a granular level," said Preiss, citing as an example an ibook picture e-book on dinosaurs. Each is pictured on a two-page spread and, Preiss told PW, "we can tag each dinosaur and someone online can search for each individual species in the book. As information increases and finding a specific piece of information begins to be like finding a needle in a haystack, DOI will be critical." When readers encounter a DOI link online, they can click through to buy the book, get reviews and excerpts, information about the author, related titles and other information.