Acoustics is an advanced field which enjoys a never ending youth and novel innovations in this field are introduced by either the search for a better comprehension, or by technological innovations. Micro-fabrication methodologies introduced a complete novel class of microdevices, which exploit acoustic waves for several different tasks, specifically for sensing purposes and information processing. Performance enhancements are achievable by optimized modelling tools, which are able to deal with more complicated configurations, and through more enhanced strategies of fabrications and of integration in technological systems, for example wireless communications. This book primarily deals with modelling and fabrication methods for microdevices, including unusual configurations and phenomena. Theoretical studies and modelling strategies are discussed, for phenomena ranging from the revelation of cracks to the acoustics of the oceans.