The fi eld of environmental forensic studies combines science – both the natural and social sciences – with investigation. The key term and variable is that of ‘evidence’, and the purpose of forensic study is to ensure that the gathering and interpretation of information conforms to the highest levels of scientifi c rigour and validity. This requires critical scrutiny of sources of data, the yardsticks by which to measure harm, and close consideration of who is saying what and for what reasons. As this chapter indicates, effective environmental forensic study involves a wide number of stake-holders and types of information. It is a complex area in which to work.