Possible Clues:

• "The Giving Tree" author Silverstein
• "Falling Up" poet/illustrator Silverstein
• Silverstein of kiddie lit
• 'Spaghetti' songwriter Silverstein
• 'Where the Sidewalk Ends' writer Silverstein
• 'The Yipiyuk' author Silverstein
• Name on the cover of “The Giving Tree”
• 'A Light in the Attic' poet Silverstein
• "A Light in the Attic" poet Silverstein
• Silverstein with two Grammy Awards