This paper introduces the concept of a hybrid system and some of the challe
nges associated with the stability of such systems, including the issues of
guaranteeing stability of switched stable systems and finding conditions f
or the existence of switched controllers for stabilizing switched unstable
systems. In this endeavor, this paper surveys the major results in the (Lya
punov) stability of finite-dimensional hybrid systems and then discusses th
e stronger, more specialized results of switched linear (stable and unstabl
e) systems. A section detailing how some of the results can be formulated a
s linear matrix inequalities is given. Stability analyses on the regulation
of the angle of attack of an aircraft and on the PI control of a vehicle w
ith an automatic transmission are given. Other examples are included to ill
ustrate various results in this paper.