This tutorial introduces the General Feedback Theorem (GFT). Feedback systems are usually designed with the familiar single-loop block diagram in mind. Various nonidealities, such as unavoidable minor loops and direct forward transmission, make the single-loop block diagram progressively less useful. The GFT defines a natural block diagram model that is identical in format to the single-loop model that is conventionally assumed, thus providing a desirable link between general feedback theory and a detailed circuit diagram analyzed in terms of factored pole-zero transfer functions. The GFT is illustrated on a potentially unstable Darlington emitter/source follower stage, and leads to design criteria that limit the maximum peaking regardless of the value of the load capacitance. Another example is a two-stage feedback amplifier having various nonidealities, including loading interactions at all points, direct forward transmission, and two minor loops. The GFT is computer friendly, and emphasis is on the numerical and graphical results obtained by use of an Intusoft ICAP/4 circuit simulator.