The book covers the historical period from the first third of the 19th century until 1991, when the Russian Empire, and then the USSR, firmly and confidently asserted their military-political presence on the southern borders of the country. The coordinated and concentrated efforts of diplomatic, military and intelligence government agencies made it possible to reliably ensure compliance with the national security interests of Russia and the Soviet Union in the Central Asian region and Afghanistan on the basis of compliance with the principles of international law and respect for the sovereignty of the neighboring state. The main attention is paid to the analysis of the reconnaissance and subversive activities of the intelligence services of NATO, Pakistan and Iran against the Soviet border troops during the strategic cross-border operation on Afghan territory in 1979–1989 and to a description of the counterintelligence work of the special departments of the USSR KGB for border troops.