Possible Clues:

• Logical intro?
• Sphere or system starter
• Friendly opener?
• ''The Island of the Day Before'' author
• "Foucault's Pendulum" author Umberto
• 'Foucault's Pendulum' author Umberto
• Umberto —, author
• Prefix with footprint or friendly
• Prefix with "tourism"
• ''Baudolino'' author