While solid-state amplifiers offer far better specifications, many audiophiles believe that vacuum tube amplifiers sound "better". In particular, the single-ended triode (SET) has been at the forefront of the reemergence of vacuum tube amplifiers. Without taking sides in the solid-state versus tube debate, this book starts with the lowly electron and builds the theoretical basis for the design of a SET amplifier. The final chapters present a complete SET example from design to construction. Like other books in the "From Scratch" series, no prior knowledge of the subject matter is assumed.