The calculus is probably the most useful single branch of mathematics. ...I have found the ability to do simple calculus, easily and reliably, was th… - Richard Hamming

This is a book about thinking. One cannot talk about thinking in the abstract, at least not usefully. But one can talk about thinking about digital filters, and by studying how great scientists thought about digital filters, one learns, however gradually, to think like a great scientist.

Probability plays a central role in many fields, from quantum mechanics to information theory, and even older fields use probability now that the presence of "noise" is officially admitted. The newer aspects of many fields start with the admission of uncertainty.

Continuous distributions are basic to the theory of probability and statistics, and the calculus is necessary to handle them with any ease.