This book explores the types and processing of olives, olive oil, and its by-products, which are increasingly recognized as an important supply of bioactive compounds. By using unique biotechnological processing methods, the value of olive mill by-products can be upgraded, thus establishing a sustainable circular economy. Bioactive polyphenols such as oleuropein obtained from olive industry by-products can be applied to develop innovative products such as nutraceuticals and cosmeceuticals. It must be emphasized that consuming extra virgin olive oil and table olives is an important part of the Mediterranean diet, offering significant benefits to human health and reducing the risk of many chronic diseases.