This book is about a dynamic vision of chemical and biochemical phenomena from the world of contemporary chemistry and biochemistry, the main features of which are: structure, function and reactivity. It deals with concepts concerning the various ways in which it is possible to visualize the molecular structure of the substances that go to make up our universe. It looks at molecular synthesis as if it were dealing with molecular architecture - actually, that is really the way things are, given that the whole world is composed of small molecular fragments which connect with each other in more or less complex ways until they achieve the target molecule. The elements that lie behind all this molecular scenery - the historical development of the main concepts that underpin a dynamic vision of the molecular structure of the world we live in - provide us with a better understanding of the historical and philosophical vision of scientific areas such as chemistry, biochemistry and medicine presented by the author.