I've eyed The Poisoned Pen as a destination for years now but I actively avoid Scottsdale so it took the newly opened Cornish Pasty Co. two blocks down to get me to visit. Super clean and well organized store, and it's not all mystery! They had a great selection of classics and popular books, as well as a used section and several "general stuff" items. I loved that there's a whole shelf dedicated to Sherlock Holmes! They have a ton of signings and events also, so definitely check out their calendar.
Really lovely place.