The metal-oxide-semiconductor transistor (MOST) offers the possibility of integrating large amounts of switching circuitry on a small area of semiconductor. Potential advantages stemming from this are low cost, reliable logic and storage arrays fabricated from active elements only in a relatively simple production process.The design of uni-channel and complementary MOST circuits, and the relationship between device parameters and circuit performance, are described in the first part of the paper. The second considers ways in which storage arrays might be assembled, with particular reference to the problems of inter- and intra-connection of circuit elements.Practical results for circuits using discrete devices are given. It is probable that integration would produce at least a doubling of the speeds obtained and a much lower power consumption.