For the past 20 years, science readers all over the country have looked forward to reading The New York Times on Tuesdays, because that is when the Science Times section appears. One of the section's enduring features is the "scientists at work" column, in which a major scientist s profiled each week. The purpose of this column is two-fold: to bring attention to some of the most important work being done in science, and to associate a name and a face to that work. The columns are written by The Times's science journalists, who are some of best in the business: Gina Kolata, William Broad, Malcolm Browne, James Glanz, John Noble Wilford, Natalie Angier, Sandra Blakeslee, etc. The science is rigorously explained and the personalities are brought to life. Who are the most important scientist? (They'are not necessary the most recognisable names) What motivates them? What are their opinions? What are they like? What is their influence? About 50 profiles are included in the book, grouped by general discipline and chosen based on the lasting importance of the scientist's work, interest in the scientist as a personality, and the quality of the profile itself. The Times' writers have updated the material where needed an added sidebars to expand on the science an it into context. A photo accompanies each profile to put a face to the name.