There have been some extraordinary developments in chemistry during the 20th century. This book explains some of these advances and describes some that are likely to happen in the future. These include the many remarkable discoveries made in the life sciences, and the wide variety of technological applications of chemistry - liquid crystals, batteries, catalysts and new electronic materials. The book also deals with the practical aspects of chemsitry - for example, methods of making and analyzing molecules, ways of calculating their properties and studying how and why chemical reactions occur.