Abstract: When is a measure-preserving transformation isomorphic to its inverse? There are partial solutions to this problem (for certain classes of transformations), but it is also known to be, in some senses, not fully solvable. We'll briefly review some of the classification and anti-classification results and then describe what is known for the class rank-1 transformations. We'll then state and prove a classification result for canonically bounded rank-1 transformations.