Possible Clues:

• 'Tattered Tom' author Horatio
• Horatio ____ ( Novelist )
• Big name in juvenile book collecting
• US diplomat who chaired the founding conference of 5 11 - but was later accused of spying
• Horatio who wrote "Tattered Tom"
• Horatio who wrote "Ragged Dick"
• Horatio who created Ragged Dick
• Horatio who wrote rags-to-riches tales
• Hiss of history
• Big name in juvenile fiction history