Microcantilever sensor systems have recently attracted much attention as a promising and highly sensitive approach to "label-free" detection of biomolecules. These techniques have the potential to be developed into a robust framework for disease diagnostics, genomics research, and drug discovery. In this book, a wide range of biomolecular systems including DNA nanomotor, polymer brushes and proteins have been investigated using microcantilever systems for biosensing and nanoactuation appli­cations. Both single cantilever and multiple cantilever array detection systems were introduced. In particular, the technical details regarding the design, construction and calibration of a microcantilever detection system were given to provide some general introductory information for micro­cantilever beginners.