I studied Physics as an undergraduate at the University of Exeter and then did my PhD in the Cavendish Laboratory, University of Cambridge, where later I held a Royal Society University Research Fellowship. I was also a Fellow of Murry Edwards College (formerly New Hall), where I taught physics and mathematics. After a brief excursion from academic life to set up my first company, I moved to Sheffield Hallam University to take up the Chair of Materials Analysis in the Materials and Engineering Research Institute (MERI). I moved to the EEE Department in University of Sheffield in 2003. My research career started with instrument development to record coherent electron diffraction patterns. Results from this led me to have an idea about how to improve transmission microscopes for atomic imaging by using an inverse computational method, now referred to as ‘ptychography’. My original formulation of ptychography proved to be rather harder to do experimentally than I expected, and so I gave up on it at the end of the 1990s. However, I returned to it afresh in the 2000s, developing a completely new iterative solution to the phase problem. Ptychography has since become a standard technique in X-ray microscopy, and has made substantial impact in EUV, electron and visible-light microscopy. I continue to develop various forms of it. I set up a second company (Phase Focus Ltd [link: www.phasefocus.com]) in 2006, working for it part time as Chief Scientific Officer until 2015.