N. G. Basov – one of the greatest scientists of the 20th century

Some ideas of Nikolai Gennadievich Basov, which were proposed by him in the period from 1960 to 1965 and realised by his colleagues under his guidance and with his participation, are reported. They include the concept of a "space maser" (a satelliteborne ammonia gas maser); prediction of dynamic chaos (strange attractor); laser amplifier and the possibility of designing this amplifier with an ultimate (single-photon) sensitivity; image intensifier; formation and amplification of target images in laser location; ring-cavity regenerative amplifiers; coherent summation; and semiconductor lasers using laser pumping as a first example of coherent summators (beam combiners).