This presentation gives a brief introduction into requirements engineering. It presents industrial data, which shows that requirements engineering is one of the most critical phases of product development. Nevertheless, it is commonly the most neglected phase, which results in projects to be abandoned, unhappy customers and a lot of rework. After defining some key concepts of requirements engineering, metrics will be given that help make requirements testable. The second part of the presentation then describes a model of the requirements engineering process consisting of elicitation, analysis, documentation and validation. Techniques and tools will be given that can be used in each one of these phases to help improve the requirements engineering process. These will include a leading software tool for requirements engineering as well as some less well-known tools that have proven to be very effective.