Among Wittgenstein scholars, the prevailing view has been that the differences between Wittgenstein's Tractatus and his later Philosophical Investigations represent a fundamental change in his philosophical outlook. Robert John Ackermann challenges this perception and calls for a major reassessment of this significant thinker. Ackermann argues that Wittgenstein's writings are best analyzed as a broad survey of language confusions and possible clear usage. In Tractatus, Wittgenstein explored language meaning and language games--which he later realized composed only one neighborhood of his linguistic inquires. He therefore turned to new kinds of picture theories, in order to arrive at a comprehensive view of clear linguistic assertion. The result endeavor was his Investigations, in which he likened language to a city, originally created haphazardly, then surrounded by interrelated neighborhoods, all with horizons of clear meaning and each ruled by local standards of speech and behavior. The conceptual map that Wittgenstein devised shows the Tractatus and Investigations to be two of these neighborhoods and reveals the other quarters of the City to which they are linked. Acknowledging Wittgenstein's genius in recognizing that an appropriate neighborhood horizon provides the key to the meaning of clear assertion, Ackermann shows that the resulting view of meaning has profound implications for theories of language learning and language comprehension.