#365: Shelf-awareness

365 daysToday is the first anniversary of IOTD. I’d like to say thanks to all my readers, especially those who have left comments. Keep watching this space!

For people who still can’t resist the lure of buying books, being able to find the one you want, within a bulging bookcase, can be a daunting task. Even if you can be bothered to sort the damn things alphabetically, every birthday or booksale means another cartload of titles has to be added in the right positions. I’d rather spend the time reading the contents than searching the spines.

Today’s invention is a way to find the book you want, without having to do any manual shelf sorting.


Almost every book now published has a barcode printed on the back. Each time a new book is bought (or a read one replaced), you scan in the barcode using the reader attached to your bookcase.

Each shelf has a narrow strip of continuously barcoded plastic attached across the width of the bookcase. As each book is replaced, it must be set on the shelf so that it stands, for a moment, between its new neighbours and covers a section of the barcode tape, corresponding to the width of the book.

Whilst in this position, the scanner is used to record the sequence on the tape running up to the front of the book and after the back face. This specifies where the book is and is recorded by the system. The book can then be pushed backwards off the tape and into position. This will automatically update the locations of all the books on that shelf (by an amount which decreases with distance from the replaced book).

The tape also carries human-readable numbers so that the system, when asked, “Where is my copy of Ulysses?” can respond “It’s at indicator 20115 in bookcase 3. It was last accessed one year ago. Your library is now 2301 replacements away from alphabetical ordering”.

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