 There are issues in the philosophy of biological experimentation that also arise in other experimental sciences, for example, issues that have to do with causal inference, experimental testing, the reliability of data, the problem of experimental artifacts, and the rationality of scientific practice. Experimental biological knowledge is sufficiently different from other kinds of scientific knowledge to merit a separate philosophical treatment of these issues. In addition, there are issues that arise exclusively in biology, such as the role of model organisms. In what follows, both kinds of issues will be considered.