Luis L. Bonilla received his Ph.D. in physics from the Universidad Nacional de Educación a Distancia (UNED), Madrid, in 1981. After conducting postdoctoral research for three years at the Mathematics Department at Stanford University, he took positions as associate professor at the Universities of Sevilla and Barcelona, both Spain. In 1992, he accepted his current post of Professor of Applied Mathematics at the University Carlos III in Madrid. Professor Bonilla's research interests lie in the modeling and asymptotic analysis of nonlinear problems in condensed matter physics, including electronic and mechanical properties. He is the author and co-author of more than 180 research papers and book chapters.

Stephen W. Teitsworth received his Ph.D. in Physics in 1986 from Harvard University, where he also carried out postdoctoral research. For the past several years, he has been a faculty member of the Physics department at Duke University. His current research interests center on experimental and theoretical studies of nonlinear electronic transport and optoelectronic properties of semiconductor-based materials, with a focus on spatially periodic systems such as superlattices.