It was "W.H. Smith Books" when I moved to Ottawa in 1985. Back then, they had three times the floor space for the store itself and a spiral staircase to the basement for staff to bring stock up to the shelves. As bookstore chains went, they were as high-end as Ottawa got.
Having been swallowed up into the Chapters-Indigo maw, and with a Chapters "box" on the other side of Confederation Square from the Sparks Street Mall, however, that may have been the end of it for this long-serving storefront.