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In page Peanuts:

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The Peanuts characters have been featured in many books over the years.[1][2] Some represented chronological reprints of the newspaper strip, while others were thematic collections such as Snoopy's Tennis Book, or collections of inspirational adages such as Happiness Is a Warm Puppy. Some single-story books were produced, such as Snoopy and the Red Baron. In addition, many of the animated television specials and feature films were adapted into book form.[citation needed]