Editorial 1 Tribologie + Schmierungstechnik · 69. Jahrgang · eOnly Sonderausgabe 1/ 2022 DOI 10.24053/ TuS-2022-0024 Ladies and Gentlemen, Lubricants help to keep our systems running: They protect our machine elements from wear and corrosion and in this way ensure a long service life and smart operation. As diverse as our machines are, as diverse the lubricants must be to optimally fulfil the specific requirements of a particular machine system. Today’s machines are becoming more and more powerful thanks to permanent research and development. Thus, even the constantly growing demands on lubricants cannot be met without well-founded scientific research. Kurt Lewin, German social psychologist, put it in a nutshell: Nothing is more practical than a good theory. In other words: Science and practice belong together. No progress without science, no real progress without putting the knowledge gained into practice, and no money for further research without economic success in practice. Our journal, starting from the editorial team, the editor, the publisher, the many authors, and advertisers are committed to the transfer of scientific knowledge into practice. And of course, you, dear reader: You are a very important element in this chain, because lubrication does not happen by itself. Without you, the final step is missing. Lubrication must be organised and done. Best of all, on a solid basis. In this special edition, we present a selection of expert papers from the OilDoc Conference 2021. The international conference and technical exhibition, which has been taking place every two years since 2011, also aims to bring together all those involved: Scientists, designers, oil experts, manufacturers of lubrication systems, testing technology and sensors, maintenance specialists and the service companies that support them, for example for oil monitoring and oil care. The special profile of the conference is the mix of expert lectures, the high level of practical relevance and the direct contact with leading experts and companies from the various specialist areas during the breaks, at the exhibition and the evening events. Therefore, our invitation: Stay tuned so that your machines run better and better. And perhaps we will see you - at the next OilDoc Conference in May 2023! Petra Bots & Rüdiger Krethe OilDoc Akademie Reliable machine lubrication means lifelong learning