The London-based bookseller has released results of a study "proving market demand for e-textbooks and confirming their value as a new revenue stream for publishers".

Tony Newson, digital and online manager at John Smith & Son, said: "The e-textbook programme is a major component of a series of initiatives John Smith is undertaking as we adapt to meet the rapidly changing textbook market.

"With an increase in e-textbook sales over 20 times last year's units, we anticipate that the programme will grow for the 2009 autumn semester as publishers recognise that offering rights-protected, digital content is a powerful means of driving revenue growth while also enriching the learning experience."

John Smith is using Ingram Digital's interactive e-textbook platform VitalSource to power its e-textbook programme.

E-textbooks were sold using various sales models, with bundled print and e-textbooks proving the most popular channel.

According to John Smith's study, the digital availability of textbooks led to a reduction in used textbook sales, which force publishers to compete with their own material leading to more frequent new editions and, therefore, higher costs for printed textbooks.

The company chose VitalSource for its ability to support multiple formats, flexible digital rights management and interactive features such as the ability to search within text, highlight in the book, copy and paste sections, and share notes with classmates and professors.

The e-textbook programme was expanded for the 2008 autumn semester, following a successful pilot in 2007, with almost 100 of John Smith's bestselling textbook titles now available in digital and print.