A brief history of the application of computing techniques emphasizes the two-part development with expensive minicomputers available in a few laboratories being added to by inexpensive microcomputers ubiquitously available. Computers are used for microscope control and plotting, serial section reconstruction, morphometric measurement, stereology, video image analysis, photometry and fluorescence microscopy. Basic principles are exemplified by considering nerve cell reconstruction. General principles of computerized electrical measurement including filtering, averaging and stimulus generation are discussed. Computerized waveform selection as used for spike discrimination, when considered along with computer control of electrode position and the growing availability of multichannel recording arrays, suggests a possible advance in automatic analyses. With the ability to process more complex waveforms successfully, electrophysiological data such as compound extracellular potentials may usefully replace the cleaner, but more limited intracellular data. Success with multichannel feedback controlled stimulators making paraplegics stand and walk point to a developing application with much potential.