Intellectual giants provide broad shoulders for subsequent inventors. Their unfinished inquiry, however, also casts shadow on the prospect of future research. This paper incorporates this shadow effect into a two-stage innovation process and shows that patenting the first-stage result (the basic invention) may enhance the second-stage innovation. It is optimal to reject patent protection to the basic invention only when this beneficial effect does not arise, and when it is essential to preserve the pioneering inventor's incentive to continue research activities.