The first edition of this book was described by the "British Medical Journal" as 'a concise and clear account of the basics of pharmacokinetics which could not be faulted in any way.' Since it was published in 1981, there has been an enormous increase in the quantity of published pharmacokinetic data, in its quality and in its analysis. In addition to the great interest in pharmacokinetics in medicine there is now a greatly increased reliance upon pharmacokinetics to help in the design and interpretation of animal toxicity tests carried out to evaluate drug safety. This expansion of the data and interest in the subject reinforces the need for this simple introductory text aimed at students of pharmacy, pharmacology, human or veterinary medicine.