Ozzie D, NP-hard 
Porter Square Books is moving to University Hall (what I think of as Porter Exchange, in a building which was originally a Sears) in October. Their new space will be 40% bigger, and stay open later. They'll have more cafe space too -- but it won't be Cafe Zing, which is staying in the shopping plaza -- instead it will be a new cafe, "Page and Leaf" (another venture by the owners of Diesel, Bloc, and Forge).
https://www.shelf-awareness.com/issue.html?issue=4793#m64830
Porter Square Books celebrates 20 with a move that will revive long-empty spaces in Lesley hall - Cambridge Day
Porter Square Books is celebrating its 20th birthday with a move to Lesley University’s University Hall, around 1,000 feet away, with new cafe partners, restaurants as neighbors and potentially even longer weekday hours.
Cantabridged