Black holes under external influence

The work on black holes immersed in external fields is reviewed in both test-field approximation and within exact solutions. In particular we pay attention to the effect of the expulsion of the flux of external fields across charged and rotating black holes which are approaching extremal states. Recently this effect has been shown to occur for black hole solutions in string theory. We also discuss black holes surrounded by rings and disks and rotating black holes accelerated by strings. The content corresponds to the lecture given at ICGC 2000 in Kharagpur. Sections 2–6 are based on the text of the lecture on ‘Electromagnetic fields around black holes and Meissner effect’ given at the 3rd ICRA workshop in Pescara 1999 (to be published with T Ledvinka in Nuovo Cimento).