Today, only a few people outside of the scientific community are conversant with the tradition of science and its many breakthroughs. The rest are scientifically illiterate. So say Frank R. Spellman and Joni Price-Bayer, authors of In Defense of Science: Why Scientific Literacy Matters. This book explains why ordinary citizens need to have an understanding of science, its methods, and its groundbreaking discoveries. The authors introduce the most basic scientific concepts in accessible and straightforward language. Along the way they debunk several misconceptions of science and scientists, and arrive at a view of science as an integral part of society, policy, and everyday life. The book begins with an introduction to science and its basic concepts, including a brief and entertaining history of science and scientific discoveries, before taking on current views of science in society. It surveys the many sources of our ideas of science, including pop culture, classics of literature, news media, and political discourse. Much of the information from these sources tends to mislead, and the only way to guard against such misinformation is to become scientifically literate, and promote scientific literacy in society. The book therefore delves into the reasons that so many people do not understand basic scientific principles and do not keep up with scientific breakthroughs, and finishes by examining the current state of science education. It includes many resources for further reading, and is presented in an engaging and entertaining way. It offers much food for thought for anyone concerned with science in today's world.