To the layman (me) - we always hear about the likes of the Blackbird and U2 bomber - and then later on the F-117 and B2 bomber as these great advancements in warfare technology. I've never heard what would be considered the pinnacle of Russian warfare technology during this period. It always seems to me that the Russians were playing catch-up and would look to adapt pre-existing US technology that they may have been procured through espionage or other means. (This could be wrong but its the impression I'm under reading back through the Cold War)