Since the first edition of this book the major advances have been in column packings, where over ninety per cent of separations are w performed using chemically bonded microparticulate packings, and in instrumentation. The use of microprocessor control has brought about a rationalization of mobile phase delivery systems and in detectors, the introduction of electrochemical and spectrophotometric detection other than in the ultra-violet region, has widened the field of applications and the sensitivity of the technique. The use of ion- pair chromatography has increased at the expense of ion-exchange and this together with the improvements in detectors has greatly increased the appli- cation of the technique in the biomedical field. These advances are described together with the established methods to enable the beginner to carry out a satisfactory separation and to gain the experience necessary for the full exploitation of the technique. R. J. Hamilton P. A. Sewell Liverpool,1981 1 Introduction to high performance liquid chromatography 1. 1 Introduction Chromatography in its many forms is widely used as a separative and an analytical technique. Gas chromatography since its introduction by James and Martin  has been pre-eminent in the field. Uquid chromatography in the of paper, thin-layer, ion-exchange, and exclusion (gel permeation and gel form filtration) chromatography had t been able to achieve the same success, mainly because of the poor efficiences and the long analysis times arising from the low mobile phase flow rates.