The device is mainly a lockpicking device, but can also be used to scan books, as Tosh was surprised to discover. The title book scanner is not only conjectural, but an wholly wrong description.
Talk about it here.
The device could also be used to store text and other data in the form of photograph-like images. Merely by waving it at printed text and images, it could record and store them as information inside itself or transfer the data to a computer. Despite Torchwood Three's policy that alien artefacts must never leave the Hub, Toshiko Sato took the scanner out several times in order to experiment with it. (TV: Everything Changes)
Toshiko later used it to translate the words that the Duroc-possessed Owen Harper spoke soon after his revival. This, however, did not work, something which she claimed it had "never done before". She used it again within the same adventure to unlock a hospital door. Owen stole it from her, distracting her with a kiss, and used it to relock the door, sealing Tosh outside while he fought Duroc. (TV: Dead Man Walking)
Behind the scenes Edit
Torchwood website Edit
The series 1 version of the Torchwood website featured "current investigations" on alien technology by Tosh. She said of the book, "It's brilliant — kind of like an iPod for books. It can take any book, and scan it in seconds, and transfer the text any storage device [sic]." While testing it out at the library, Tosh claimed it had "limitless" storage capacity. Tosh speculated the device originated as part of an archaeological survey team which waved the scanner over carvings on some planet, and then translated the writing on the journey home.