This new "FRCEM PRIMARY: All-In-One Notes" provides comprehensive information for understanding the anatomy, physiology, biochemistry, pharmacology, microbiology, haematology, pathology and evidence-based medicine required for preliminary examinations. It remains the leading emergency medicine textbook for candidates preparing for this examination. Given the rapid growth of medical knowledge and time pressures, it is only sometimes possible to read a comprehensive account of all topics or read individual textbooks independently. Therefore, a method had to be developed to summarise all the information required for the main examination, explain concepts, and cover any information that might be questioned in a concise and precise manner. For these reasons, the introductory book was condensed for the first time in 2015. The original idea was to be a ready source of well-prepared and informative topics that are useful "in the field" and prepare the reader for deeper learning. The colourful format of the book and the use of diagrams make it possible to learn concepts in depth while getting a quick overview of the most important topics that have been asked and are likely to be asked. Furthermore, the new layout and the numerous additional colourful pictures and illustrations help the candidate to convert abstract information into easily retrievable mental images using the visualisation and association technique and make it easier to find information.