This work gives a full description of a method for analyzing the
admissible complex representations of the general linear group G =
Gl(N, F) of a non-Archimedean local field F in terms of the
structure of these representations when they are restricted to certain
compact open subgroups of G. The authors define a family of
representations of these compact open subgroups, which they call simple
types. The first example of a simple type, the "trivial type," is the
trivial character of an Iwahori subgroup of G. The irreducible
representations of G containing the trivial simple type are classified
by the simple modules over a classical affine Hecke algebra. Via an
isomorphism of Hecke algebras, this classification is transferred to the
irreducible representations of G containing a given simple type. This
leads to a complete classification of the irreduc-ible smooth
representations of G, including an explicit description of the
supercuspidal representations as induced representations. A special
feature of this work is its virtually complete reliance on algebraic
methods of a ring-theoretic kind. A full and accessible account of these
methods is given here.