Whenever two bodies are in rubbing contact, macroscopic phenomena as friction, adhesion and wear are inevitably experienced. The practice of controlling such phenomena has been part of the technique and technology development during all the human evolution stages. However, despite of the longstanding practical approach to the problem, the methodological investigation is instead much more recent. Actually, the investigation of friction, adhesion and wear is carried out as a part of a wider research activity involving physics, chemistry, material science and engineering. In this book we review specific aspects of the lubrication fundamentals and dry contact mechanics, with particular emphasis on the theoretical investigation of the role of fluid rheology and surfaces roughness on the contact mechanics at dry/lubricated interfaces.