The Waveguide Handbook is an unabridged reprint of the book first published in 1951 by McGraw Hill as Volume 10 of the MIT Radiation Laboratory Series. Although the primary aim of the book is to present the equivalent-circuit parameters for a large number of microwave structures, a brief but coherent account of the fundamental concepts necessary for their proper utilisation is included. The first three chapters summarise both the field and network theoretic considerations necessary for the derivation and utilisation of the basic transmission line-equivalent-circuit formalism. The mode concept and transmission-line formulation of the field equations are introduced in Chapter 1. This chapter contains an engineering treatment of the transmission-line theory necessary for the description of propagating and nonpropagating modes in the more important types of uniform and nonuniform waveguides. The field-structure, propagation, attenuation, etc., characteristics of the transmission-line