This book provides an overview of the topic of mineral oils, specifically focusing on the quality and use of turbine oils. The complexity of turbine oils is captured, covering aspects such as manufacturing processes, quality requirements, analytical testing methods, as well as their physical-chemical properties, key evaluation criteria, operational limits, and waste oil disposal. Oil oxidation is discussed in detail. The topic is linked to a presentation of alternative methods of electricity generation and initiatives for climate protection. The book aims to inspire research projects related to new, rapid methods for quality assessment of turbine oils, the development of new correlation methods, and potential extensions of oil usage times in operations, thereby contributing to increased economic efficiency while promoting sustainable use of oil resources.