ABSTRACT
Throughout Part One we have expanded our attention successively from free modules to summands of free modules to submodules of free modules. In the present chapter we will discuss factor modules of free modules and of projective modules. This discussion represents the ultimate expansion of our attention since, as we shall see, every module is isomorphic to a factor module of a free module. This fact was implicit in the verification of Observation 1 of §3.1. We shall give a more thorough discussion here.
