The Idea Store in Bow, east London, has an adult and children's library, a reference and information service and three learning laboratories with computers and audio-visual aids.
Sergio Dogliani, the store's manager, says the place is unusual in so far as users are able to talk, eat and use their mobile phones - activities that are normally forbidden in libraries.
The intention is to make the store more attractive and welcoming to adult learners. It opens in the daytime and during the evenings, seven days a week, and runs a creche for some classes.
Tower Hamlets college did some research which showed that people wanted more welcoming learning venues opening at non-traditional times.
The average ward in the borough has a very high percentage of adults with poor basic skills - indeed one, Spitalfields, has the highest percentage in England.
The Idea Store, which offers classes in adult basic skills, computer literacy and English for speakers of other languages, is the first of seven to be built in the borough as part of a pound;30 million investment programme.