Very often when you start to research a topic, you need to fill in some gaps with background information. Books provides history, context, and overviews. You'll find both ebooks and print books here.
Use "Jane's All the World's Aircraft: Unmanned" to search for specifications and history of drones or other unmanned aircraft.
Available Modules:
Aero-Engines
Air and Space Defence Module
Airport Review
All the World's Aircraft: Development & Production
All the World's Aircraft: In Service
All the World's Aircraft: Unmanned
C4ISR & Mission Systems: Air
C4ISR & Mission Systems: Joint & Common Equipment
Country Risk Daily Report
Defence Industry
Defence Weekly
Flight Avionics
Intelligence Review
Intelligence Weekly
International Defence Review
Islamic Affairs Analyst
Militant Propaganda Analysis
Missiles and Rockets
Navy International
News Module
Simulation & Training Systems
Space Systems & Industry
Terrorism & Security Monitor
Terrorism Watch Report
Weapons: Air-Launched
Weapons: Naval
Weapons: Strategic
World Defence Industry