Greek philosophers first hypothesized that matter was composed of atoms, but the theory would not resurface again until the late 17th century. The idea that that atoms joined to form structures called molecules first appeared in the 19th century and helped explain why gases, liquids, and solids behave differently from one another. In the 20th century subatomic particles were discovered-electrons, protons, and neutrons-and atomic structure was finally...

Evolution is the process through which living things change with time, adapting to the changing environment around them, and new species form. Fossils provide important evidence for the theory of evolution, but so too do other kinds of evidence, such as the distribution of modern species, animals' appearance, and DNA. This book offers a comprehensive and lavishly illustrated account of Darwin's observations and theory of evolution, the body of knowledge...

Ten thousand years ago, life was different. People were nomadic, and their life spans were short. During this time, people practiced trepanning, one of the early human medical procedures. Today, the diseases that wiped out millions just a few hundred years ago have been completely eradicated thanks to developments in medicine. Readers explore some of the earliest medical discoveries, how medicine has developed, and how it continues to have an impact...