Book excerpt: First Published in 1996. This volume reprints pieces from the Vienna Circle period between the manifesto and the adoption of semantics, as well as two commentaries. During this period, the logical empiricists were the most ambitious and the most confident about the success of their enterprise. The first section consists of four ideological classics, The second section reprints three papers on physicalism. The third section consists of three papers on logic and the fourth on reprints three papers on truth, induction, and confirmation.