Originally published: New York: Pocket Books, 2001.

Ninth Key 2005, Turtleback Books

ISBN-13: 9780606330862

Turtleback School & Library edition

Hardcover

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Ninth Key 2004, Avon Books, New York, NY

ISBN-13: 9780060725129

Mass-market paperback

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Ninth Key 2004, Turtleback Books, New York, NY

ISBN-13: 9781417701728

Turtleback School & Library edition

Hardcover

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