The paper was a result of my PhD thesis research from 1974 to 1977. When I started my work at the Department of Electrical Engineering and Computer Science of the University of California, Berkeley, nobody believed that you could realize analog integrated circuits using MOS technologies (actually, all analog integrated circuits realized at that time were using bipolar technologies). It was the Department of EECS in Berkeley that pioneered the analog MOS (and later CMOS) design. This work was carried out by a group guided by Berkeley professors Paul R. Gray, R. W. Brodersen, and David A. Hodges. They created an environment that attracted gifted young engineers from all over the world who generated a number of new ideas. It was this work that laid down the foundations of analog CMOS design.