Early stealth involved camouflage with like natural objects, the first time troops were clothed in drab colors was in the 17th century, when British troops experimented with it. Submarines in the 18th and 19th century gave craft at sea the ability to hide from surface warships, reaching full potential in WWI and WWII. Dazzle camouflage was used in WWI and somewhat in WWII to confuse ships at sea in terms of rangefinding, not to keep them from being seen. Yehudi lights were used in WWII to brighten aircraft approach to blend in with a light sky. Radar rendered this approach obsolete, but then countermeasures were needed to confuse radar waves. Finally in 1958 the A12, later developed into the SR-71 had a measure of what we now think of as stealth technology both in shape and materials. Later stealth fighter methodologies turned from angular and slab-sided(Have Blue/F-117) to blended(F-22, F-23, F-35, B2 bomber), and this was eventually used on warships, such as the Skjold Class, Arleigh Burke and French Lafayette Class.
In the 1950s a US scientist first postulated a particle accelerator to block radar. In the 1960s, Project Oxcart attempted to block air inlets with an electron beam generator. The Soviet Union claimed a new "stealth" plasma device was being tested in 1999, both on aircraft and tanks, and in the early 2000s both the US and France also was working on the application of this for aircraft. The technology could form a layer or cloud of plasma around a vehicle to deflect or absorb radar, from simpler electrostatic or radio frequency discharges to more complex laser discharges. Newer methods may involve "meta-materials" that structure reflective properties of materials to mimic their surroundings. Scientists at Duke University were able to use a series of rings that propagate radio waves around an object so that the radiation entering the ring structure pass through with little interference, essentially rendering the object less visible in the presence of radio waves.
In SF early stories of invisibilty include 1859's "What Was It" about a natural invisible creature. Several other stories appeared before HG Well's popular "Invisble Man". He also posits moving very fast will cause one to be invisible in his "The New Accelerator", adapted by the BBC BBC Wells
. In 1939, invisible aliens appeared in "Sinister Barrier". In 1966, Star Trek took the idea of submarine warfare, and created a spaceship that bent the rays of light around it to render it invisible. In later years, Doctor Who, Star Wars, and Predator used cloaking technology to great effect. Stealth technology has appeared in the movie "Firefox", "Stealth".