Microengineered reactors are a new type of reactor. Their novelty dictates a new approach in design, which requires familiarization with the various manufacturing techniques and materials, and with differences in fluid behaviour and dominant phenomena in the microscale. New approaches for energy management, catalyst incorporation and integration of functions and unit operations can be employed. Microengineered reactors have some unique characteristics which create the potential for high performance chemicals and information processing, These include efficient mass and heat transfer and precise control of the hydrodynamic environment. They can provide significant advantages in information generation in high throughput experimentation and process development, and from difficult to obtain operating regimes. In terms of chemicals manufacture, they allow distributed, mobile and intensified processing. This technology, still in its infancy has the potential to change the chemical engineering landscape.