This article provides an exhaustive typology of the uses of foreign law in order to provide insight into whether foreign law can be appropriately used in constitutional interpretation, when it can be used, and what the stakes and parameters are in each case. In doing so, the article addresses two significant problems in the debate on foreign law. First, much of the commentary has focused on the justifications for using foreign law and the principled or practical arguments against using foreign law. But the focus on the why of foreign law has obscured the more basic question about the ways in which foreign law can be used, that is, the how of foreign law. Focusing on the why of foreign law threatens to generalize arguments into debates on "foreign law" as a whole when debating particular methods of foreign law usage may be more helpful. Some methods of use may be more easily justified and others totally unjustifiable. The second problem is one of exhaustiveness. Some scholars have recognized the need to focus on the how of foreign law, but they have identified only a limited set of ways in which foreign law could be used. This limited categorization of foreign law usage prevents clear evaluation of which uses are appropriate. This article's typology demonstrates that most uses of foreign law are not problematic, and as a result, that the foreign law debate should focus specifically on the few uses that are potentially problematic, rather than on "foreign law" more generally.