The rapid development of set theory in the last fifty years, mainly by
obtaining plenty of independence results, strongly influenced an
understanding of the structure of the real line. This book is devoted to
the study of the real line and its subsets taking into account the
recent results of set theory. Whenever possible the presentation is done
without the full axiom of choice. Since the book is intended to be
self-contained, all necessary results of set theory, topology, measure
theory, and descriptive set theory are revisited with the purpose of
eliminating superfluous use of an axiom of choice. The duality of
measure and category is studied in a detailed manner. Several statements
pertaining to properties of the real line are shown to be undecidable in
set theory. The metamathematics behind set theory is shortly explained
in the appendix. Each section contains a series of exercises with
additional results.