Although it is hardly possible to keep up with advances in technology, it is reassuring to know that in science
and engineering, development and innovation are possible through a solid understanding of basic principles.
The theory of signals and systems is one of those fundamentals, and it will be the foundation of much research
and development in engineering for years to come. Not only engineers will need to know about signals and
systems—to some degree everybody will. The pervasiveness of computers, cell phones, digital recording, and
digital communications will require it.