Paul Callaghan is the Alan MacDiarmid Professor of Physical Sciences at Victoria University of Wellington; the head of the MacDiarmid Institute for Advanced Materials and Nanotechnology; and the founding director of Magritek, a company that sells nuclear magnetic resonance instruments. He has published more than 200 articles in scientific journals and is the author of Are Angels OK?: The Parallel Universes of New Zealand Writers and Scientists; As Far As We Know: Conversations about Science, Life and the Universe; and Principles of Nuclear Magnetic Resonance Microscopy.