Recent developments in gravitational lensing in observational cosmology

It has been now widely recognized that gravitational lensing is an indispensable research method in various areas of astronomy. In our previous review, we gave a pedagogical introduction of the subject and some applications in cosmology by that time. Since then, progresses in observations as well as theories of gravitational lensing have been remarkable and various works have been conducted. In this review, we highlight some of these developments.