  In these lecture notes we give an introduction to Bridgeland stability
conditions on smooth complex projective varieties with a particular focus on
the case of surfaces. This includes basic definitions of stability conditions
on derived categories, basics on moduli spaces of stable objects and variation
of stability. These notes originated from lecture series by the first author at
the summer school "Recent advances in algebraic and arithmetic geometry",
Siena, Italy, August 24-28, 2015 and at the school "Moduli of Curves", CIMAT,
Guanajuato, Mexico, February 22 - March 4, 2016.
