power systems; optimization of expansion and operation of power generation systems; transmission and distribution of electricity; and electricity sector regulation including issues related to transport, supply security, the design of regional wholesale markets and rates and, more recently, the sustainability of energy models and universal access to energy. Mid-1970s to mid-1980s: Power systems control and stability analysis His contributions in the field of electrical engineering began with the completion of his PhD at MIT under the supervision of Prof. Fred Schweppe, in which he formulated a new technique for the dynamic analysis of small perturbations of electric power systems known as Selective Modal Analysis. This analytical framework allows approaching large and complex linear time-invariant dynamic system problems (such as dynamic stability analysis, or the determination of coherent generator groups and dynamic equivalents in transient stability studies) through a reduction technique that extracts the relevant quantitative and qualitative information. This framework was later applied intensively to solve different power system stability and control problems, such as the analysis of the oscillatory stability and control, subsynchronous resonance or multi-area analysis of small signal stability. Mid-1980s to mid-1990s: Models for power systems and industrial applications In the late 1980s and early 1990s, his research was focused on the development of new algorithms and methodologies to support the operation and planning of electric power systems. Among other contributions, he developed pioneering models for computation of spot prices in interconnected power systems and decomposition approaches to tackle optimal reactive power planning problems. During this period he also contributed to computer-aided optimization design of electrical machines and other industrial equipment and to the development of expert systems with applications to the design and incipient default detection in industrial systems. Mid-1990s to mid-2010s: Economics and regulation of electric power systems and markets In the early 1990s, in the context of the Argentinean power sector restructuring, he began working on the analysis of the best regulatory methodologies for pricing power transmission services, formulating the principle of beneficiary pays for network cost allocation. Since then, he has devoted a major part of his research activities to the regulation and restructuring of the power industry. He carried on with the seminal works of his mentor Prof. Schweppe on marginal pricing theories applied to power systems; on the generation side, he formulated the foundation for wholesale pricing considering generation operation and planning constraints and identifying the reasons for mismatches in capital