Possible Clues:

• ''Where's __?'' (kid-lit series)
• One hard to find
• Well-hidden fellow of children's books
• Ralph — Emerson, US poet/essayist
• Not just another face in the crowd?
• "Where's ___?" (children's book series)
• Guy to find in kids' books
• One in a crowd at a bookstore?
• Ralph — Emerson, author
• Character found in picture books