  In this presentation, I review recent work with Mike Appels and David
Kubiznak on thermodynamics of accelerating black holes. I start by reviewing
the geometry of accelerating black holes, focussing on the conical deficit
responsible for the 'force' causing the black hole to accelerate. Then I
discuss black hole thermodynamics with conical deficits, showing how to include
the tension of the deficit as a thermodynamic variable, and introducing a
canonically conjugate {\it thermodynamic length}. Finally, I describe the
thermodynamics of the slowly accelerating black hole in anti-de Sitter
spacetime.
