Technological needs for chemical, ionic and biological species detection are giving rise to continuous research and development in physico-chemistry and biology. The constant progress being made in the theoretical and technological aspects concerning studies and developments of chemical sensors, biosensors and biochips is presented in this book by different scientists and professors from different universities and constitutes an updating of the state of the art for chemical sensors, biosensors and biochips. This book places a large emphasis on interaction between chemical and biological species, in a gaseous or liquid state, and details mineral and biological materials acting as sensitive elements. The role of electrical, electrochemical, piezoelectric and optical transducers in detection mechanisms are presented through their developments and from a performance point-of-view. Micro-reactors, nanotechnologies and flexible substrates, are considered in relation to their role in neural networks. Contents 1. Chemical and Biological Recognition, Nicole Jaffrezic-Renault. 2. Adsorption Phenomena, René Lalauze. 3. Microcantilever Transduction, Isabelle Dufour. 4. Piezoelectric Transduction (QCM), Hubert Perrot. 5. Metal Oxide Gas Sensors, Christophe Pijolat. 6. Molecular Material-based Conductimetric Gas Sensors, Marcel Bouvet. 7. Responses and Electrical Properties of Gas Microsensors, Khalifa Aguir. 8. Gas Microsensor Technology, Philippe Menini. 9. Multisensors: Measurements and Behavior Models, Philippe Breuil. 10. Development of Microtechnologies for the Realization of Chemical, Biochemical and/or Biological Microsensors, Pierre Temple-Boyer. 11. Development of Micro-preconcentrators for the Detection of Gaseous Species at Trace Level, Jean-Paul Viricelle. 12. Microfluidics: Manipulation of Nanovolume Samples, Louis Renaud. 13. Electrochemical Biosensors, Chantal Gondran. 14. Fiber-optic Biosensors, Neso Sojic. 15. In Vivo Analyses with Electrochemical Microsensors, Stéphane Arbault. 16. Microbial Biosensors for Environmental Applications, Gérald Thouand and Marie José Durand. 17. Biofuel Cells, Serge Cosnier.