This book remindedmeof the unforgettable creative atmosphere in the late 1960s in the laboratory ofmyPh.D. advisor N.G. Basov (at that time already a Nobel laureate in physics, who shared the prize in 1964 with A.M. Prokhorov and C.H. Townes). One of the experimental groups at that time includedV.S. Zuev, P.G. Kryukov, and R.V. Ambartsumyan, who were working on an exceptionally important problem /&j4I