  The basic concepts of factorizable problems in one-dimensional Quantum
Mechanics, as well as the theory of Shape Invariant potentials are reviewed.
The relation of this last theory with a generalization of the classical
Factorization Method presented by Infeld and Hull is analyzed in detail. By the
use of some properties of the Riccati equation the solutions of Infeld and Hull
are greatly generalized in a simple way.
