A fifth grade class just arrived at the library to participate in a new class project – “research and book selection”. It's their final class just before lunch. When class is over, 30 students are blitzing the Librarian to check out their books so they can hustle to the cafeteria. A third of the students had their library cards with them. A third of the students left their cards in their lockers and had to run to retrieve them, and the final third couldn't find them. So the Librarian relied on the tried and true “look them up manually” method. After approximately 10 minutes of “controlled mayhem”, the Librarian has completed this task with only two questions: What books did I check out, and to which students? After all, lost books can cost thousands of dollars to replace.

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