This essay will first examine the attempts to categorize and label procedural systems, an impulse that many comparatists cannot, but should, resist because the very exercise of creating categories invites undue generalizations. The focus will then shift to procedural harmonization, a term that encompasses a number of topics of increasing importance to proceduralists. This section forms the centrepiece of the essay because it is here that most opportunities to benefit from comparative scholarship present themselves—and are still being missed. After illustrating the dynamics and results of regional, particularly European, and supra-regional harmonization initiatives, this section identifies trends towards harmonization through private rule making and examines principles that determine the scope of, and limits to, procedural harmonization. The final section addresses the growing concern about access to justice, specifically cost considerations and claim aggregation techniques, which prompt the somewhat related questions of whether and to what extent one legal system can borrow procedural rules from another one.