Introduction. 1. Chemical Atomism and the Evolution of Chemical Theory in the Nineteenth Century; A.J. Rocke. 2. The Creative Power of Paper Tools in Early Nineteenth-Century Chemistry; U. Klein. 3. An Early History of Alexander Crum Brown's Graphical Formulas; C. Ritter. 4. Conventionalities in Formula Writing; P. Laszlo. 5. Paper Tools and Fictional Worlds: Prediction, Synthesis and Auxiliary Hypotheses in Chemistry; P.J. Ramberg. 6. Aspects of Paper Tools in the Industrial-Academic Context: Constitutions and Structures of Aniline Dyes, 1860-1880; C. Reinhardt, A.S. Travis. 7. Molecular Models and the Articulation of Structural Constraints in Chemistry; E. Francoeur. 8. Paper Tools and Molecular Architecture in the Chemistry of Linus Pauling; M.J. Nye. 9. Graphic Representations of the Periodic System of Chemical Elements; B. Bensaude-Vincent. 10. The Periodic Table: The Ultimate Paper Tool in Chemistry; E. Scerri. 11. A Principle Written in Diagrams: The Aufbau Principle for Molecules and its Visual Representations, 1927-1932; B.S. Park. 12. Fedoroff's Translation of McClintock: The Uses of Chemistry in the Reorganization of Genetics; E. Grosholz. 13. Mathematics, Representation and Molecular Structure; R.F. Hendry. 14. Affinity, Additivity and the Reification of the Bond; S.J. Weininger. Index.