Amsterdam: Printed by Heinricum Wetstenium, 1684. Vellum. 4to (8.1", 20.6 cm). , 598 40  pp. Latin. Francesco Guicciardini (editor).
First edition: The preeminent Swiss theologian of his time (not the 20th-century philosopher), Heidegger (1633-1698) was a professor of Hebrew, philosophy, dogmatics and ecclesiastical history, moral philosophy, and theology. This is a chief example of his influential writings, which were largely leveled against the Roman Catholic Church; though not antagonistic, all his works were on the list of forbidden books. The Protestant Reformation sought to end church injustices and hierarchies and sought secular religion, priests relieved of celibacy, and dismissed opulence. Post-reformation, Heidegger sought to unify the Swiss Reformed churches, still organized as separate entities. Also, the Age of Enlightenment of the 17th century characterized by the scientific revolution, philosophers circulating their ideas, and printed works served to undermine the authority of the monarchy and the church.
Encyclopaedia Britannica. British Library online. CERL online. Heritage Auctions catalogue of 2015. Catalogue of the Library of the Late William R. Williams, STD, LLD. of 1896, Part II, Item no. 686. Rear pastedown with bookplate of Rev. William Robert Williams noted for his library of church history and theology remarkable for its breadth and historic provenance; title-page with small William R. Williams on upper outer corner. Contemporary vellum binding, author and title neatly written at top of spine. All edges speckled red. Red and black text to title page. Decorated capitals and endpieces. Ex-library with Newton Theological Institution subtly labeled on spine and blind-stamped to upper-right corner of title-page, p.3, p.301, and p.597. Vellum binding lightly soiled and lightly bowed, trace of pale foxing, and handful corner creases. Well-preserved, tight, and clean. Very good+. Item #880