Imagine a library system that knows where every book is and allows visitors to return and issue books automatically. That dream is slowly becoming a reality as libraries adopt the use of tiny Radio Frequency Identification (RFID) tags for tracking books and audiovisual items.

Tiny RFID tags can store detailed information about an item, which is then sent via radio waves to a reading device - either a handheld or fixed unit. The technology is used for tracking the movement of goods in the retail industry, but it is making inroads in other areas, such as library management systems.

The Vatican Library in Rome is the latest, and one of the most high profile, of scores of libraries worldwide that are adopting RFID tagging of books and other items. During the past year, the library has tagged 50,000 of the 120,000 volumes in its public reading rooms. It plans to tag 2m of the Vatican's 40m piece collection over the next few years.

The main benefit is that books can be checked quickly using a handheld reader, reducing stocktaking time from weeks to half a day. Each book also retains details of its usage, which can be read in an instant. The tag can be used as a security device, triggering alarms if a book is removed without being issued. With automated check-ins, it can allow 24-hour returns, like a video shop.

Because most libraries have library management IT systems, the data for the tags can be generated from the library's database. The data can include a number of fields such as the book's unique identifier, loan record and bar code number.

The tag, costing around 45p, is manually stuck into the book's inner spine or close to the spine in the inside cover, sometimes using special non-damaging glue. The library then uses handheld readers to perform stocktakes, while fixed readers at issuing desks scan books entering or leaving the library. A stack of books can be scanned in seconds, significantly reducing the time and staff needed to manage loans. In some libraries, this activity has become partly self-service.

According to The RFID Knowledgebase, a research service, US libraries lead the world in RFID use, with the UK and Japan equal second. It estimates that 35m library items have been tagged worldwide.