Tribology is formally defined as the 'science and technology of interacting surfaces in relative motion and of related subjects and practices'. It includes the research and application of principles of friction, wear and lubrication. Recently, tribology on the small scale had been gaining ground. Frictional interactions in microcomponents are becoming increasingly important for the development of new products in mechanics, chemistry, electronics, life sciences, sensors and by extension for all modern industry. This book aims to provide the research and review studies in tribology. The first three chapters provide information on hydrodynamics lubrication and advanced lubricants. The fourth chapter is focused on machine friction as diagnostic tool. The following three chapters deal with influence of tribological parameters on the friction and wear. The chapters eight and nine are dedicated study of some aspects tribology of composite materials. The last chapter of this research book is focused on scale effects in adhesive contact and friction of rough surfaces.