'The Defence of the Realm' by Christopher Andrew offers an in-depth look into MI5's history, from its 1909 inception to modern-day challenges. This authoritative account, based on declassified documents, explores the agency's pivotal role in UK security, espionage, and counter-terrorism efforts.

'Every Spy a Prince' by Dan Raviv is a captivating deep dive into the Mossad's secretive world, revealing the daring operations and human stories behind Israel's famed intelligence agency. A must-read for espionage enthusiasts.