What is the nature of Kant's new 'transcendental' logic, and how is it to differ from the traditional logic? Many have argued that transcendental logic is distinguished by the domain of understanding it investigates - whether by focusing on a domain excluded from traditional logic, or by focusing a more specific domain. Here I argue that transcendental logic should not be characterized by a difference in domain at all, but rather in terms of the aspect of understanding at issue: while traditional logic investigates the form of understanding, transcendental logic studies its content. This interpretation fits better with Kant's claim that the transcendental-logical categories and the traditional-logical forms "completely coincide." It also clarifies Kant's doctrine of the spontaneity of our understanding, by highlighting what our understanding is capable of achieving on its own.