Commonwealth Books is a hidden gem located in Downtown Crossing in Boston, at the corner of Washington and Spring Lane. This cool, cute bookshop in the alley offers tons of awesome used and rare books, with a fantastic selection across many genres and decades. Its extensive holdings include art, poetry, history, fiction, and a quite strong antiquarian selection. The store also has really cool maps, old photos, old prints, and antique pictures spanning from the 1600s. It is a very cool detour for the historical aspect, with well-organized books. The staff are super nice, friendly, and helpful. It is a great place to find unique and interesting things, with very reasonable offerings. The store is open seven days a week.