Black holes under external influence

The work on black holes immersed in external fields is reviewed in both tes t-field approximation and within exact solutions. In particular we pay atte ntion to the effect of the expulsion of the flux of external fields across charged and rotating black holes which are approaching extremal states. Rec ently this effect has been shown to occur for black hole solutions in strin g theory. We also discuss black holes surrounded by rings and disks and rot ating black holes accelerated by strings.