Candide (French: Candide, ou l'optimisme) is a 1759 satirical novella by Voltaire. It's eponymous hero is a young man who lives a sheltered existence on his uncle's estate under the tutelage of Doctor Pangloss, a philosopher who subscribes to Leibniz's dictum that 'all is for the best, in the best of all possible worlds.'
When Candide is forced out into the wider world, he is confronted with a series of episodes which illustrate the bankruptcy of this optimistic worldview, most famously the Lisbon earthquake of 1755.
Free online texts
Gutenberg: Candide, EPUB, HTML, MOBI and TXT formats.
Internet Archive: Candide, or All for the Best, translated by Walter Jerrold (1898). EPUB, MOBI, PDF and TXT formats.
Standard Ebooks: Candide. AZW3, EPUB, KEPUB and Advanced EPUB formats.
University of Adelaide (Internet Archive): Candide, translated by William F. Fleming. EPUB, MOBI and HTML formats.
Wikisource: Candide, translated by Tobias Smollett. HTML and other formats.
Gutenberg: Candide, ou, l'optimisme. EPUB, HTML, MOBI and TXT formats.
Wikisource: Candide, multiple editions. HTML and other formats.
BBC Radio 4 In Our Time: Voltaire's Candide. Melvyn Bragg with David Wootton, Nicholas Cronk, Caroline Warman.
Librivox: Candide (multiple versions). Free public domain audiobooks.
Wikipedia: Voltaire - Candide
Bloom's Western Canon: Candide is listed.
Leibniz: The Monadology and The Theodicy.
Swift: Gulliver's Travels - a satirical influence whose author Voltaire had met.
Voltaire: Philosophical Letters - discusses the execution of Admiral Byng, an event later worked into the plot of Candide.
French Language resources