DeGroat's (Happy Birthday to You, You Belong in a Zoo) fifth book starring Gilbert follows the furry fellow on a school outing to Pilgrim Town. When he gets stuck with Philip the tattletale as his field trip buddy, Gilbert tries to give him the slip. But Philip proves that he can be a true friend when Gilbert gets into a jam. Though the author sprinkles in a few tidbits about pilgrim life, she deemphasizes the historical backdrop to stress instead the themes of friendship and gratitude. Ages 5-8. (Aug.)