Environmental site investigation and characterization is potentially the most important part of an environmental project. Site investigation is so important because nearly all other aspects of the project, from financial decisions to engineering designs and construction tasks, are based on the findings of an initial site investigation. The goal in site investigation is to use a number of methods to understand the conditions present at a site and to choose a clear and detailed method to record and present the findings for later reference. Economic and political factors often play a large role in the depth and accuracy of environmental site investigations. This text takes readers step by step through the site investigation process. The knowledge needed for site investigation is presented on an introductory level so that students and practitioners can see the great importance that site investigation lends to the overall success of a project. Additionally, by gaining a thorough understanding of the current state of technology and methodology used for environmental site investigation, readers will better understand how to make their site investigations more efficient and beneficial to a project.