I have been moving in industrial enterprises for all my life and I participate in building of machine tools. My effort is to manage that theory and practice can create one unit complementing and respecting each other. For these reasons, the large team of authors consists of people working in practice as well as of people acting at technical universities. It is not easy to work with such a team of authors, neverthleless, it is always necessary to keep in mind that theory cannot exist without practice and practice cannot exist without theory. ukryj opis