This book includes famous papers such as 'The Problem of the Essential Indexical' and 'Frege on Demonstratives' and 'Cognitive Significance and New Theories of Reference'; papers co-authored with Mark Crimmins ('The Prince and the Phone Booth') and David Israel ('Fodor on Psychological Explanations') and related papers on situation semantics, direct reference, and the structure of belief. Perry has added 'afterwords' that discuss responses to his work by Gareth Evans, Robert Stalnaker, Barbara Partee, Howard Wettstein and others. The word 'I' is called an 'indexical' which means who it stands for depends on who says it, not just on its meaning. Other indexicals are 'you', 'here' and 'now'. Perry discusses how these words work, and why they express important philosophical thoughts. He claims that indexicals pose a challenge to traditional assumptions about language and thought, and for that reason a number of these papers sparked lively debates.