Tiziana Di Matteo is a Professor in the McWilliams Center for Cosmology of the Physics Department at Carnegie Mellon University, USA. She received her PhD in 1998 at Cambridge University, UK. She was a Chandra Fellow at Harvard and a junior faculty member at the Max Planck Institute for Astrophysics in Germany. Di Matteo is a theorist with expertise in both high energy astrophysics and cosmology. Her interests focus on state-of-the-art cosmological simulations of galaxy formation with special emphasis on modelling the impact of black holes on structure formation in the Universe. Andrew King is Professor of Theoretical Astrophysics at the University of Leicester and holds visiting appointments at the Universities of Amsterdam and Leiden. During his career he has been awarded a PPARC Senior Fellowship, the Gauss Professorship at the university of Goettingen, a Royal Society Wolfson Merit Award, and the RAS Eddington Medal. He is an author and co-author of several books, including Stars, a Very Short Introduction, and Accretion Power in Astrophysics. His research interests include accretion disc structure, supermassive black hole growth and feedback, active galactic nuclei, compact binary evolution, and ultraluminous X-ray sources. Neil J. Cornish is Regents Professor of Physics and Director of the eXtreme Gravity Institute at Montana State University. He completed his Ph.D. at the University of Toronto, followed by postdoctoral fellowships in Steven Hawking's group at the University of Cambridge and in David Spergel's group at Princeton University. Neil is a multiwavelength gravitational-wave astronomer, and he is a member of the Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) Collaboration, and the NASA Laser Interferometer Space Antenna (LISA) Science Study team.