In 1975, Putnam published a paper called "The Meaning of 'Meaning'", which challenged the orthodox view in the philosophies of language and mind. The article's "Twin Earth" conclusions about meaning, thought and knowledge were shocking. This work contains writings on the subject of "Twin Earth".

Part 1 Where It All Began; Chapter 1 The Meaning of "Meaning", Hilary Putnam; Part 2 Natural Kinds and Philosophy of Language; Chapter 2 Putnam's Theory on the Reference of Substance Terms, Eddy Zemach; Chapter 3 Natural Kinds, D. H. Mellor; Chapter 4 Putnam on Artifacts, Stephen P. Schwartz; Chapter 5 From Intentionality: Are Meanings in the Head?, John Searle; Chapter 6 Natural-Kind Terms, Kim Sterelny; Part 3 Mental Content and Mental Causation; Chapter 7 From "Individualism and the Mental", Tyler Burge; Chapter 8 Other Bodies, Tyler Burge; Chapter 9 From "Beyond Belief": Notional Attitudes, Daniel Dennett; Chapter 10 Social Content and Psychological Content, Brian Loar; Chapter 11 From Psychosemantics: Individualism and Supervenience, Jerry Fodor; Chapter 12 Functionalism and Broad Content, Frank Jackson, Philip Pettit; Chapter 13 On What's in the Head, Robert Stalnaker; Chapter 14 From Mental Content: Twin Earth and Teleology, Colin McQinn; Chapter 15 A Modal Argument for Narrow Content, Jerry Fodor; Chapter 16 All the Difference in the World, Tim Crane; Chapter 17 Putnam on Mind and Meaning, John McDowell; Part 4 Self-Knowledge; Chapter 18 Knowing One's Own Mind, Donald Davidson; Chapter 19 Individualism and Self-Knowledge, Tyler Burge; Chapter 20 Anti-Individualism and Privileged Access, Michael McKinsey; Chapter 21 Can Externalism Be Reconciled with Self-Knowledge?, Akeel Bilgrami;