Under 35 U.S.C. 112(a), Patents must include a written description. USPTO guidelines state "To satisfy the written description requirement, a patent specification must describe the claimed invention in sufficient detail that one skilled in the art can reasonably conclude that the inventor had possession of the claimed invention." The description may be in the claims. Under the doctrine of inherent disclosure, undisclosed but inherent properties may support claims. This is particularly true for provisional patent applications, which often include inherent disclosures of properties that are later explicitly disclosed in the utility application.