From January to December, I SPY Year-Round Challenger is chock-full of gorgeous photographs taken from previously published I SPY books as well as all-new riddles from Jean Marzollo. With one spread for every month, readers will delight in finding their favorite holidays, their birthday month, as well as dozens of clever objects hidden within the images. I SPY Year-Round Challenger ISBN: 0-439-31634-0 I SPY logo is a trademark of Jean Marzollo and Walter Wick. All rights reserved.