How should we allocate property rights in unowned tangible and intangible resources? This Article develops a model of original acquisition that draws together common law doctrines of first possession with original acquisition doctrines in patent, copyright, and trademark law. The common denominator is time: in each context, doctrine involves a trade-off between assigning entitlements to resources earlier or later in the process of their development and use. Early awards risk granting exclusivity to parties who may not be capable of putting resources to their best use. Late awards prolong contests for ownership, which may generate waste or discourage acquisition efforts in the first place. While the doctrinal resolution of these timing questions varies in different resource contexts, the determination depends upon a recurring and discrete set of functional considerations. This Article applies its theory to assess a host of doctrinal features in our patent, copyright, and trademark laws, to analyze recent intellectual property law developments, and to suggest directions for reform.