In the past few years a wide variety of applications of neural networks to pattern recognition in experimental high energy physics has appeared. The neural network salulions are in general of high quality, and. in a number of cases, are superior to those obtained using 'uaditionar methods. But neural networks are of particular interest in high energy physics for another rason as well: much of the pattern recognition must be performed online, i.e., in a few microseconds or less. The inherent parallelism of neural network algorithms. and the ability to implement them as very fast hardware devices, may make them an ideal technology for this application.