This Brief presents in a self-contained non-technical and illustrative fashion the
state-of-the-art results and techniques for the dynamics of extremal black holes. Extremal
black holes are roughly speaking either maximally rotating or maximally charged. Astronomical
observations suggest that near-extremal (stellar or supermassive) black holes are ubiquitous in
the universe. The book presents various recently discovered characteristic phenomena (such as
the horizon instability) that have enhanced our understanding of the dynamics of extremal black
holes. The topics should be of interest to pure mathematicians theoretical physicists and
astronomers. This book provides common ground for communication between these scientific
communities.
