ABSTRACT
While these principles may form much of the foundation of toxicology, when it comes to any specific substance there is likely to be controversy. Disagreement may arise on the relative importance of any one of these principles while trying to evaluate implications for public health. Exploring these principles is an essential first step before examining their application to any specific substance. This chapter will explore some of the details and issues surrounding these principles, but first it is appropriate to put them in historical context.
