I would first like to acknowledge all the expert chapter authors associated with this textbook. Many of them have been close professional friends for many years, and I am deeply honored to be a colleague of theirs. There are more than 300 years of collective experience in laboratory medicine among this highly distinguished group of authors. I extend my deepest thanks to those at McGraw-Hill who have been involved in the production of this book, now for three editions. I am delighted that this book has been included in the Lange series of medical books, which has such a proud tradition in medical education. It is especially exciting to watch the book grow into a global source of information in the field, with its translations into three languages from its original English version, with more to come. Thank you to all the translators and publishers outside the United States who have made this possible.