Geraint F. Lewis is a Professor of Astrophysics at the Sydney Institute for Astronomy, University of Sydney. He undertook his undergraduate education at the University of London before gaining a Ph.D. in Astrophysics from the Institute of Astronomy, University of Cambridge. Professor Lewis is an internationally recognised astrophysicist, and has published more than two hundred papers in a diverse range of fields, including gravitational lensing, galactic cannibalism, cosmology and large-scale structure. As well as being an accomplished lecturer, he regularly engages in public outreach through public speaking, articles in the popular press, and social media. Luke A. Barnes is a postdoctoral researcher at the Sydney Institute for Astronomy, University of Sydney. His university medal from the University of Sydney helped him earn a scholarship to complete a Ph.D. at the University of Cambridge. He has published papers in the field of galaxy formation and on the fine-tuning of the Universe for life. He has been invited to speak at the 2011 and 2015 St Thomas Summer Seminars in Philosophy of Religion and Philosophical Theology, the University of California Summer School for the Philosophy of Cosmology, and numerous public lectures.