So there were a few of these kinds of gizmos. The Soviets famously had a poison-shooting umbrella which they used to assassinate a Bulgarian dissident. The Stasi had [a whole collection](http://alexwellerstein.com/publications/wellerstein_statesecrets(endeavour).pdf) of amusing little trinkets for disguising information and weapons in apparently normal household objects. Tiny cameras and tiny microphones were, of course, used by all sides, though the most famous example was the hiding of a microphone in a wooden version of the Seal of the United States that was in the US's Moscow Embassy. The Stasi manufactured a bra camera that could be hidden in cleavage.

We know more about the Soviet side of these things because the US likes to write about them, but the US and UK had their own versions of these kinds of gizmos. The US was at its most James Bondian when it cooked up various strange schemes for assassinating Fidel Castro (including, potentially, with exploding cigars, though this may just be a myth).

If you want to see more of this stuff than is good for you, the International Spy Museum in Washington, DC, is almost nothing but this kind of stuff.

The problem for me, as a historian of science and technology in particular, is that most of this stuff was pretty inconsequential, and focusing on it misses the actual technological marvels of the Cold War. The really amazing spy technology of the Stasi is not their little cameras; it is the machine they developed that helped automate the reading 90,000 pieces of East German mail per day, or the machine that allowed them to first digitize fingerprint records (before the FBI did!). The really amazing American tech bits are not tiny microphones, but the fact that they were able to use high-level mathematics, computers, and other means to break what were thought to be cryptographically secure Soviet communication schemes, to say nothing of developing spy planes like the U-2, or spy satellites like CORONA. And the Soviets' umbrella is something of a silly novelty in context (there are easier ways to kill people); their recruitment of high-level moles in the US intelligence services were far more deadly and effective and impressive. And while some of these attempts can seem rather silly, the CIA's interest in psychotropic drugs and coercive interrogation techniques can be slotted into the same sort of approach, and their results were pretty damn grim (and their tortuous legacies still haunt us today with things like water boarding).

So yes, the gadgets are interesting, but there is a way in which they can actually distract from both the actually consequential Cold War intelligence technologies, and can make the Cold War intelligence game seem like an action movie when it was really something a little darker than that.

Someone already answered this question, but I think you should be aware of places where you can see some this stuff up close.

If you're in the US: International Spy Museum in Washington D.C.

In the UK: Imperial War Museum has a spy exhibit. It's a hop skip from Elephant & Castle.

Both are absolutely incredible.

"Spycraft: The Secret History of the CIA's Spytechs, from Communism to Al-Qaeda" by Robert Wallace and H. Keith Melton, with Robert Schlesinger. (New York: Dutton, 2008) is a great read concerning spycraft, gadgets and the people who made them