The Open Library project of the Internet Archive initiative just updated their online BookReader with some very compelling features for the growing number of digital readers including:
• improved and larger screen layout,
• navigation bar including chapter markers that show your progress
• a read-aloud feature
• improved full-text search
More than two million digitized books (and other items) are available free from The Open Library and Internet Archive including 449 e-textbooks published between 1518 and 2014 including many public domain books from the turn of the 20th century which can be read online. The more recent publisher textbooks appear to be just web pages that identify the title, author, cover and offer locations for borrowing a physical copy or places to buy.
Internet Archive has also recently doubled the number of books available to the print disabled by providing free access to more than 1 million books in the specially designed format, Daisy, to support those with visual impairments. These include classic 19th century fiction and current novels to technical guides and research materials.