Biological membranes play a significant role in a range of biological processes such as ion-transport and signal transduction. Over the years much effort has been devoted towards developing an understanding of biomembrane structure. The study of this subject is now reaching an important stage. This is because at last the full three-dimensional structure of certain membrane proteins is beginning to be resolved. In the past three-dimensional structures of membrane proteins were difficult to obtain as only two dimensional crystals were available. In recent years satisfactory crystals have been obtained and X-ray diffraction techniques have been applied. This has led to the three dimensional structures of the photosynthetic reaction centres, porins and more recently the structure of cytochrome oxidase. Of course not all membrane proteins are readily crystallisable and some are not even available in sufficient quantities to obtain the necessary crystals or to carry out biophysical experiments. In some cases e.g. the voltage-gated potassium ion channel membrane proteins their structure has been proposed mainly on the basis of molecular biology methods. This has prompted the search for alternative approaches for characterising biomembrane structure. Molecular biological studies are providing a wealth of information on a number of different membrane proteins. Combining the information derived from such studies with molecular modelling is becoming extremely useful for relating structure to function. Development of other approaches include synthesis and structure- function analysis of peptides corresponding to functionally important domains of membrane proteins. This book presents a series of Chapters discussing how a combination of molecular biological, biophysical and theoretical (molecular modelling) techniques are helping us to obtain a much clearer picture of biomembrane structure. After an introductory Chapter on the Principles of membrane Protein Structure, the book is divided into two sections; one dealing with crystallographic approaches and the other non-crystallographic approaches such as NMR, AFM, SPR and FTIR spectroscopy. Chapters dealing with the recently solved crystal structure of cytochrome oxidase and bacteriorhodopsin are presented. The book contains contributions from leading membrane scientists describing their latest studies. It provides an up to date coverage of the developments in the field of biomembranes with particular emphasis on membrane proteins.