After World War II, communication and control engineering reached a high level of development. The next step may be the recasting and unifying of the theories of control and communication in the machine and in the animal on a statistical basis. This monograph represents one phase of the new theory pertaining to the methods and techniques in the design of communications; it was first published during the war as a classified report to the National Defense Research Committee. It is an attempt to unite the theory and practice of two fields of work that are of vital importance and have a...