The Cat in Numberland

At Hilbert's Hotel Infinity, the resident cat encounters a fully booked hotel whose rooms are occupied by Numbers. Both Odds and Evens fill its rooms, yet new guests continue to arrive despite the lack of vacancy. The puzzled cat faces a number-filled hotel in which a full set of rooms does not prevent more arrivals. Ivar Ekeland wrote the 56-page book, published by Cricket Books in 2006.