Programming, Software, Mathematics 

The requirements specification is a document that clearly and precisely defines the customer's logical requirements (or needs) in such a way that it is possible to test the finished system to verify that those needs have actually been met. The point is to ensure that the customer's needs are correctly defined before time, money, and resources are wasted working on the wrong solution. Typically, writing a formal requirements specification is the final step in the analysis phase of the system development life cycle. The author walks through the steps of analyzing user-centered requirements to arrive at this final document.
About the Author
In his professional life, Charles Martin is an operations research analyst whose career has focused on decision support software. With a bachelor's degree in mathematics from Harvard and a Ph.D. from the University of California, Berkeley, he is currently Director of Product Management for Valogix LLC, an inventory optimization software firm. In his personal life, Charles has always enjoyed an active life in the great outdoors and exploring beautiful new places. - from Amzon