Expander graphs have been the subject of much research for the last
three decades. These are graphs "with no bottlenecks". They are
playing an important role in a variety of areas in computer
science. The explicit construction of expander graphs is a challenging
problem, the solution of which has required a good deal of
sophisticated mathematical tools. In this survey talk, I will try to
offer a glimpse to some of the aspects of this fascinating subject.

If you want to read more about expanders, you can look
course notes on my www.cs.huji.ac.il/~nati/