  The theory of random real numbers is exceedingly well-developed, and
fascinating from many points of view. It is also quite challenging
mathematically. The present notes are intended as no more than a gateway to the
larger theory. They review just the most elementary part of the theory (bearing
on Kolmogorov- and ML-randomness). We hope that the simple arguments presented
here will encourage the enterprising student to examine richer treatments of
the subject available elsewhere, notably, in Downey and Hirschfeldt (2010).
