Not only are there two different categories of phenomena, the person and the external phenomena, there are also two different types of misconceptions with respect to the nature of phenomena: misconceptions with respect to the nature of the person and with respect to the external phenomena. This means to overcome these two types of misconception is to realize selflessness, which is the ultimate nature of these two types of phenomena. Therefore there are two selflessnesses, selflessness of person and selflessness of phenomena. Generally speaking, comparing the two, the realization of the selflessness of the person is said to be easier than realization of the selflessness of phenomena because of long familiarity with the actual self, the person.
From Gentle Bridges: Conversations with the Dalai Lama on the Sciences of Mind, edited by Jeremy Hayward and Francisco J. Varela, page 113