Pawel Penczek earned his M.Sc. degrees in physics at The University of Warsaw in 1979 for work on the digital contrast enhancement in scintigraphic images. His PhD, earned at The University of Warsaw in 1988, was devoted to the computational analysis of multi-channel electroencephalographic data. In 1989 he became a postdoctoral fellow with Dr. Joachim Frank in Wadsworth Center, Albany NY, where he participated in the first cryo-EM determination of the structure of E. coli ribosome. During his tenure in Dr. Frank’s group he contributed novel single particle and electron tomography computational methods to the widely used package SPIDER. These included reference-free alignment of noisy EM images, CTF correction methodology, dual-tilt tomography, and other. In 2000 he became a faculty at The University of Texas, Houston Medical School, where he continued development of computational methodology for high-resolution single particle EM, which led to the establishment of a modern single particle software package SPARX. His current research interests are focused on the identification of conformers in cryo-EM samples and on validation techniques for structure determination by cryo-EM. He is currently a Full Professor, with tenure, at The University of Texas and a co-director of a Structural Biology Imaging Center at the McGavern Medical School.