We review various simple analytical theories for homopolymers within a
unified framework. The common guideline of our approach is the Flory theory,
and its various avatars, with the attempt of being reasonably self-contained.
We expect this review to be useful as an introduction to the topic at the
graduate students level.Comment: Topical review appeared J. Phys.: Condens. Matter, 46 pages, 8
Figures. Sec. VIF added. Typos fixed. Few references adde