Martin Rees (Lord Rees of Ludlow, OM FRS) is an astrophysicist and cosmologist, and the UK's Astronomer Royal.  He is based at the University of Cambridge where he has been Professor of Astronomy and Director of the Institute of Astronomy. Martin is a Fellow, and was the former Master, of Trinity College, Cambridge.

Martin's main astronomical research interests have been galaxy formation, cosmic jets, black holes, gamma ray bursts, along with more speculative aspects of cosmology – in particular, whether we live in a multiverse – and the prospects of detecting extra-terrestrial life. 

He has honorary degrees from numerous universities, including Harvard, Yale, Sydney, Melbourne, Oxford and Cambridge. He has served on many bodies connected with education, space research, arms control and international collaboration in science.

In 2005, Martin was appointed to the House of Lords, and he was President of the Royal Society from 2005 to 2010.

He has been increasingly concerned in recent years about long-term global issues – the pressures that our population is placing on environment, sustainability and biodiversity; and the impact of powerful new technologies.

He is co-founder of the Centre for the Study of Existential Risk (CSER) at the University of Cambridge with a focus on these issues.

In addition to over 500 research publications, he has written extensively for a general readership with books including 'On the Future: Prospects for Humanity', and 'If Science Is to Save Us'.