A composite material (shortened to composite) is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure. The new material may be preferred for many reasons: common examples include materials which are stronger, lighter, or less expensive when compared to traditional materials. Composites are generally used for buildings, bridges, and structures such as boat hulls, swimming pool panels, race car bodies, shower stalls, bathtubs, storage tanks, imitation granite and cultured marble sinks and countertops. Composite materials are saving lives and assets around the world, every day. The lightweight and strong properties of composites make them an ideal fit for armour applications. Composites are changing the way we travel and ship goods. The most advanced examples perform routinely on spacecraft and aircraft in demanding environments. Concrete is the most common artificial composite material of all and typically consists of loose stones (aggregate) held with a matrix of cement. This book, Composites and Their Applications, deals with prospective applications and the associated properties of several composites aiming on the following numerous topics: health or integrity monitoring techniques of composites structures, bio-medical composites and their solicitations in dental or tissue materials, natural fibre or mineral filler reinforced composites and their property characterization, catalysts composites and their applications, and some other potential applications of fibres or composites as sensors, etc.