Introduction Max Cresswell, Edwin Mares and Adriane Rini; 1. Aristotle on the necessity of the consequent Adriane Rini; 2. Aristotle on one-sided possibility Marko Malink; 3. Why does Aristotle need a modal syllogistic? Robin Smith; 4. Necessity, possibility and determinism in Stoic thought Vanessa de Harven; 5. Necessity in Avicenna and the Arabic tradition Paul Thom; 6. Modality without the Prior Analytics: early twelfth-century accounts of modal propositions Chris Martin; 7. Ockham and the foundations of modal theory in the fourteenth century Calvin G. Normore; 8. Theological and scientific applications of the notion of necessity in the mediaeval and early modern periods Jack MacIntosh; 9. Locke and the problem of necessity in early modern philosophy Peter Anstey; 10. Leibniz's theories of necessity Brandon C. Look; 11. Leibniz and the lucky proof Jonathan Westphal; 12. Divine necessity and Kant's modal categories Nicholas Stang; 13. Charles Sanders Peirce on necessity Catherine Legg and Cheryl Misak; 14. The development of C. I. Lewis's philosophy of modal logic Edwin Mares; 15. Carnap's modal predicate logic Max Cresswell.