My aim in writing this book was to present a logical development of
the fundamentals of Abstract Algebra. I have endeavored to avoid
assuming anything not proved prior to its use, and particularly to avoid
illustrative examples from other parts of mathematics and elsewhere.
Such examples are often more confusing to the student than they
are helpful since the student frequently is not acquainted sufficiently
with the other material to appreciate, or in many instances, even to
understand the examples. So far as I can recall at the moment of
writing, I have deviated from this policy in only two instances: in
some exercises giving groups as rotations of the equilateral triangle
and the square, and in taking up briefly; in Chapter 5, the trisection
of the angle. These two instances may very well be omitted without
interfering with the continuity of the development.