Harnack inequalities for Ricci flow in the light of the Canonical Expanding Soliton ABSTRACT In this talk, we introduce the notion of Canonical Expanding Ricci Soliton. Roughly speaking, given any Ricci flow on a manifold M over a time interval I, we imagine the time direction as an additional space direction and construct an expanding Ricci soliton on M x I with respect to a completely new time direction. Then we will show how to apply such a new construction to derive new Harnack inequalities for Ricci flow. This viewpoint also gives geometric insight into the existing Harnack inequalities of Hamilton and Brendle.