Marx, Spinoza and Darwin presents a common thread in its argument: it shows how these authors—certainly with differences among themselves—consolidated a field of investigation that does not resort to transcendent or religious premises in approaching the phenomena they analyze. Thus, when Spinoza declared that the “will of God” is the “sanctuary of ignorance,” when Marx provocatively maintained that “criticism of religion is the premise of all criticism,” or when Darwin polemicized against a millennial creationist approach, all were taking a stand that invited us to view our world through a secular and immanent lens. In addition to this common thread, Martins discusses other issues present in the works of these thinkers, for instance the space that exists for human subjectivity from a Marxist perspective (which is not to be confused with philosophical “objectivism”): men and women are encouraged to act in the world. With this conceptual background, the concluding chapters of the book address the proliferation of some less examined Christian fundamentalisms in contemporary world, presenting an explanatory hypothesis for the phenomenon.