The aim of our book is to describe the latest developments on aging researchmethodology, building upon previous editions, and updating the contents. Current topics are to be approached from the research perspective and the underpinnings of those studies aimed at unveiling the fine pathway of aging. The chapters reflect the state-of-the-art methods and their different variations that will clarify problematic issues faced when investigating the impact of time on the biology of live beings (mainly humans). In addition, this work aims to stimulate new questions and innovative approaches from the readers. Finally, content will interest professionals from different disciplines and different levels of expertise.