Book excerpt: This book focuses on the emerging non-invasive imaging technique of Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO). FLIO reveals unique information on retinal diseases, ranging from age-related macular degeneration and vascular diseases to hereditary retinal dystrophies. Fluorescence lifetimes enable the evaluation of disease progression before irreversible structural changes occur. The image acquisition is suitable for diagnostic purposes and follow-up examinations to investigate the natural course of disease, and to monitor the effects of possible therapies. This book fills the gap between available literature and gives state-of-the-art guidance on the principles of the FLIO technique, image acquisition, and data analysis. Written by a team of expert leaders within this field, this book will be relevant for scientists and clinicians with an interest in ophthalmoscopy.