@wildmandrake@philosophy It's ten classic and very influential books. I wouldn't rank Ayer's book up with the rest of them, though. Ayer's version of logical positivism is the one usually taught to philosophy students in English textbooks on the history of 20th century, but it isn't really representative of most or the best or the most influential works of logical positivism (from the likes of Carnap, Hempel, Neurath, or Waismann).