With increasing regularity, parties to commercial contracts are agreeing in those contracts to arbitrate their disputes when they arise. Not surprising, however, once a dispute arises, parties often disagree about whether that dispute is subject to arbitration. We address in this column several recent Commercial Division decisions on applications to compel or stay arbitrations that illustrate the complexities sometimes involved in resolving these applications, particularly where overlapping agreements may apply, some with arbitration clauses and some without.