Dr John Lestone received his PhD in nuclear physics in 1990 from the Australian National University (ANU). His 20 years at LANL have included 3 years at WNR (P-division), 7 years in N-division, and 10 years in X/XCP-divisions. John has made several significant improvements in the quality of nuclear weapons diagnostic calculations, has contributed to the re-certification of both the W88 primary and secondary, and the W78 and W80 primaries, and developed new methods for studying the initiation of nuclear weapons. He developed a new particle emission mechanism that has been successful at explaining many of the properties of ternary nuclear fission. John played major roles in the development of the first Non-Destructive-Assay system used by the IAEA to accurately measure the plutonium content of breeder reactor spent fuel assemblies, and the first “user friendly” Tomographic Gamma Scanner (TGS) to be used by non-LANL experts at Rocky Flats. He has shown that the methods used, for several decades, to model the fission rate of rapidly-rotating highly-excited nuclei were flawed and developed new methods to perform this modeling in a more correct fashion. Although trained as an experimentalist, John is now a computational physicist who simulates the outcomes of theoretical models and compares the results to available experimental data.