Alexander Borst studied Biology at the University of Wuerzburg, doing his Ph.D.-Thesis with Martin Heisenberg on olfactory learning in Drosophila. In 1984, he took a position as a Research Scientist at the Max Planck Institute of biological Cybernetics in Tuebingen, Germany, switching from olfaction to the fly visual system. From 1986 to 1994, he was a faculty member at the MBL summer course ‘Neural Systems and Behavior’ in Woods Hole. In 1993, he became head of a Junior Research Group at the Friedrich-Miescher-Laboratory, Tuebingen. In 1999, he took a position as Acting Associate Professor at UC Berkeley. Since 2001, he is Director at the Max Planck Institute of Neurobiology, Martinsried/Munich, Germany, and head of the department ‘Systems and Computational Neurobiology’. Using motion vision in the blowfly Calliphora and in the fruit fly Drosophila as a model system, his research focuses on computation in single neurons and small neural circuits. His lab combines electrophysiology, calcium imaging and genetic techniques with computational approaches such as compartmental modeling and information theory trying to understand how the fly visual system computes, from the retinal images changing in time, information on the optic flow, and from that, the essential parameters needed for steering and visual course control. These computations are first defined algorithmically by input-output analysis and subsequently become investigated with respect to their implementation by the membrane properties and biophysics of the participating neurons.