In the preparation of this new edition Dr Atherden has kept in mind the original character of the book as a tectbook for those studying for degree or diploma examination in pharmaceutical chemistry in Great Britain, the commonwealth and in America, with a wider application to practicing pharmacists and chemists. \nPart 1 gives a general account, in relation mainly to the British Pharmacopoeia (BP) of certain physical and chemical methods used in determining the purity of pharmaceutical substances. Where the procedure in the United Ststes Pharmacopeia (USP) differs notably in principle, a description of the method is given. Part 2 deals mainly with inorganic compounds in common use in pharmacy, and for convenience the simpler organic salts are also included. A brief summary of the general chemistry of each element in monographs of the BP or of the USP Part 3 is a modernized treatment of organic chemistry (included electronic theory) with special reference to compounds of Pharmacopoeial standards of official substances is placed at the end of the chapters in which they naturally falt. \nThe scope and usefulness of this edition has been broadened by the inclusion of those substances of the USP which are not included in the BP and in order to keep this edition as up to date as possible mention has been made of some important drugs, not at present official but which are likely to appear in future pharmacopeias.