We know from near-infrared imaging that bars are present in more than three quarters of local disk galaxies. Several studies have recently led to the conclusion that the fraction, as well as the properties, of bars in galaxies have not changed much from a redshift of about unity to the present day. In this paper, I will briefly review the results on which this conclusion is based, and will discuss some of the implications of bars for the evolution of galaxies. Specifically, I will discuss the role of bars in fuelling gas from the disk to the nuclear regions, where starburst activity may ensue, and the relations of bars with the specific but important class of low-luminosity starbursts known as nuclear rings.