This landmark two-volume treatise draws on the work of clinicians and researchers throughout the world to provide a unique new approach to clinical obstetrics. Its aim is to determine the most effective methods of care during pregnancy and childbirth. To this end, the authors provide overviews of data taken from the available controlled trials in which alternative forms of obstetric care have been formally evaluated. Evidence on the effectiveness of these methods--both pro and con--is presented along with information about implications for clinical practice and future research. The result is the most systematic study available on the effectiveness and safety of the full range of clinical procedures, regardless of the particular emphasis or medical context of treatment.