 Allen is most well known as the author of the book, "Probability, Statistics, and Queueing Theory with Computer Science Applications".Originally published in 1978, and still in print in 2007, it is widely used as a university textbook, by practitioners of computer performance analysis, and by those wishing to apply probability, statistics and queueing theory techniques to solve problems in other fields, such as operations research, management science, engineering, and physics.At IBM and Hewlett-Packard, Allen's students were typically systems engineers and project managers, not computer scientists.