Saltus, Edgar. The Anatomy of Negation. Rev. ed. London: Brentano's, 1889. (First ed., 1886.) Other copies of the 1886 edition are downloadable from Google books, including this one. Plain text file downloadable from Ebooks.
Edgar Saltus (1855-1921) was an acclaimed writer in his day who has dropped out of history. Still, there are those who wish to rehabilitate his reputations. See, e.g. Edgar Saltus: Forgotten Genius of American Letters? by Jason DeBoer. Several works by Edgar Saltus are available at Project Gutenberg. For another take on the type of writer Saltus was, see Edgar Saltus’s Imperial Orgy. You can also get a substantial preview of Edgar Saltus: The Man
By Marie Saltus.
The Anatomy of Negation by claiming it to be a historical compendium of anti-theism. It is not really a thorough history nor is it limited to atheism, but it could best be considered an historical narrative of skeptical and heterodox thinking, told from a rather equianimous point of view. Saltus considers the first thinker to break from religious thinking to be Kapila in ancient India. There is also an extensive account of the Buddha, and Lao Tzu to round out chapter 1. Saltus moves from China and India to ancient Greece and Rome. Lucretius is the star of the Roman saga.
Chapter 3 gives us a history of Christianity. Deep into this chapter, the skeptic Montaigne makes his appearance (103ff).
Chapter 4 takes off with the saintly Spinoza, who gets a good 10 1/2 pages. Then there is a lengthy treatment of Voltaire, followed by LaMettrie, Maupertuis, d'Holbach, Diderot, and d'Alembert.
With chapter 5 we encounter German idealism--Fichte, Schelling, Hegel, and a passing mention of some of the Young Hegelians. Clearly Saltus does not understand Hegel. He gives far more attention to Arthur Schopenhauer.