This book addresses one of the major issues of modern paediatrics: the relationship between sleep and breathing in infants. The content of this book is based on author's personal experience, as well as on up-to-date findings in the field. The necessity to present most important knowledge on sleep physiology, sleep structure in infants, mechanisms supporting respiration in the normal infants, functional changes in certain sleep stages, as well as on most characteristic forms of breathing disturbances in sleep in the infants was taken into consideration. Chronobiological aspects of functional respiratory characteristics have been tackled. Much attention has been paid to the quality of infant behaviour associated with sleep disturbances and breathing disturbances in sleep, relationship between micro environmental characteristics and sleep impairments. Possible association between infant apnoea and sudden infant death syndrome is considered; mechanisms of infant' snoring in sleep and its relation to the obstructive sleep apnoea syndrome is addressed; sleep-related breathing disturbances occurring against a background of chronic broncho-pulmonary diseases are discussed. Possible approaches to clinical studies in infants with sleep-related breathing disturbances and to their treatment are considered.