The textbook "The 18kDa Translocator Protein - Implications in Cell's Functions" offers a comprehensive analysis of the 18kDa translocator protein (TSPO), which was first identified in 1977. Despite extensive research spanning nearly three decades, the specific structure and function of TSPO remain largely unexplained. The book highlights the ubiquitous presence of TSPO in cells and its essential role in various cellular processes, including steroidogenesis, cellular respiration, production of reactive oxygen species, heme biosynthesis, immunomodulation, apoptosis, and cell proliferation. Furthermore, it discusses the association of changes in the structure and expression of TSPO with various diseases. Findings from current research suggest that TSPO could be significant as a diagnostic marker and therapeutic target in the treatment of different diseases. This book is aimed at a wide audience of scientists and professionals, including cytophysiologists, pharmacologists, geneticists, transplantologists, oncologists, and neurologists.