The first comprehensive text on microhotplate-based chemical sensor systems in CMOS-technology covers all aspects of successful sensor prototyping: theoretical considerations for modelling, controller- and system design, simulation of circuits and microsensors, design considerations, microfabrication, packaging and testing. A whole family of metal-oxide based microsensor systems with increasing complexity is presented, including fully integrated sensor arrays. This represents one of the first examples of integrated nanomaterials, microtechnology and embedded circuitry.