Easy access to computers has created a revolution in the analysis of biological data. Prior to this easy access even “simple” analyses, such as one-way analysis of variance, were very time-consuming. On the other hand, statistical theory became increasingly sophisticated and far outstripped the typical computational means available. The advent of computers, particularly the personal computer, and statistical software packages, changed this and made such approaches generally available.

Much of the development of statistical tools has been premised on a set of assumptions, designed to make the analytical approaches tractable (e.g., the assumption of normality, which underlies most parametric methods). We have now entered an era where we can, in many instances, dispense with such assumptions and use statistical approaches that are rigorous but largely freed from the straight-jacket imposed by the relative simplicity of analytical solution. Such techniques are generally termed “computer-intensive” methods, because they generally require extensive numerical approaches, practical only with a computer. At present, these methods are rather spottily available in statistical software packages and very frequently require more than simple “point and click” instructions. The purpose of the present book is to introduce some of the more common methods of computer-intensive methods by providing a relatively simple mathematical description of the techniques, examples from biology of their application, and a series of software instructions for one particular statistical software package (S-PLUS).