A MiG-25 (NATO reporting name FOXBAT) is a high-speed, high-altitude (114,000 feet/35,000 meters) interceptor, from the Mikoyan and Gurevitch design bureau, intended as a counter to the cancelled U.S. B-70 Valkyrie supersonic bomber aircraft. It has fast climb and straight-line speed, and a powerful radar, but is not very maneuverable. A typical mission would involve one pass at a bomber penetrating Soviet airspace and, perhaps at the command of ground control, firing all its missiles, and then returning as it ran out of fuel.
A reconnaissance version, the MiG-25R, was observed to make Mach 3.2 flights over Israel. It was later learned that a flight at that speed destroyed a set of engines; the still very fast operational top speed was more in the Mach 2.8 range.
Viktor Belenko flew one to Japan in 1976, where it received detailed examination from Japanese and U.S. technical intelligence specialists. It was an airplane full of surprises, mostly that it was using technology considered quite old, but that worked well. Where U.S. aircraft of comparable speed, such as the SR-71 Blackbird were built of titanium, the MiG-25 was made of stainless steel. Its radar was powerful, but used 1950s level vacuum tubes.
They have been exported to various countries, and were used by Iraq in the Gulf War.