Getting started: the anatomy and physiology of clinical research / Stephen B. Hulley, Thomas B. Newman, and Steven R. Cummings -- Conceiving the research question / Steven R. Cummings, Warren S. Browner, and Stephen B. Hulley -- Choosing the study subjects: specification, sampling, and recruitment / Stephen B. Hulley, Thomas B. Newman, and Steven R. Cummings -- Planning the measurements: precision and accuracy / Stephen B. Hulley and Steven R. Cummings -- Getting ready to estimate sample size: hypotheses and underlying principles / Warren S. Browner, Thomas B. Newman, and Stephen B. Hulley -- Estimating sample size and power: applications and examples / Warren S. Browner, Thomas B. Newman, and Stephen B. Hulley -- Designing an observational study: cohort studies / Steven R. Cummings, Thomas B. Newman, and Stephen B. Hulley -- Designing an observational study: cross-sectional and case-control studies / Thomas B. Newman ... [et al.] -- Enhancing causal inference in observational studies / Thomas B. Newman, Warren S. Browner, and Stephen B. Hulley --Designing a randomized blinded trial / Steven R. Cummings, Deborah Grady, and Stephen B. Hulley -- Alternative trial designs and implementation issues / Deborah Grady, Steven R. Cummings, and Stephen B. Hulley -- Designing studies of medical tests / Thomas B. Newman, Warren S. Browner, and Steven R. Cummings -- Research using existing databases: secondary data analysis, ancillary studies, and systematic reviews / Deborah Grady and Norman Hearst -- Addressing ethical issues / Bernard Lo -- Designing questionnaires and interviews / Steven R. Cummings and Stephen B. Hulley -- Data management / Michael A. Kohn -- Implementing the study: pretesting, quality control, and protocol revisions / Stephen B. Hulley and Steven R. Cummings.