“Constructing Written Test Questions for the Basic and Clinical Sciences” (4th edition) is an item-writing manual published by the National Board of Medical Examiners® (NBME®). The manual is intended to guide educators of healthcare professions in writing high-quality, multiple-choice questions (MCQs) related to the foundational and clinical sciences. It covers the development of MCQs, common flaws related to item (question) development, and the basics of item analysis. Also, special attention is given to rules for writing one-best-answer questions in the clinical vignette format.