  The aim of this short lecture series is to expose the students to the
beautiful theory of lattices by, on one hand, demonstrating various basic ideas
that appear in this theory and, on the other hand, formulating some of the
celebrated results which, in particular, shows some connections to other fields
of mathematics. The time restriction forces us to avoid many important parts of
the theory, and the route we have chosen is naturally biased by the individual
taste of the speaker.
