The book aims at providing both students and scientists with an extensive, interesting and cutting edge description of the protein world and its applications. The second edition will contain new developments on membrane proteins, more lab nethods for studying proteins, and expanded material on cryoEM. A key goal of the second edition is to make the book more student friendly. To this end, a new chapter will be added on enzyme catalysis and its applications to protein engineering and drug design. In addition, exercises will now be included at the end of each chapter.