Born in Provence and educated as a priest, Gassendi taught at Digne and at Aix before being appointed to the chair of mathematics at the Royal College of France in Paris in 1645. His earliest work (Exercitationes Paradoxicae adversus Aristoteleos, 1624, trs. as Exercises against the Aristotelians, 1972) develops the ‘mitigated scepticism’ that characterizes much of his philosophical outlook. Gassendi had a deep respect for ancient scepticism, and his objections to Descartes’s Meditations (collected as the fifth set of objections) mount a withering attack on the foundational role of ‘clear and distinct ideas’ in Descartes’s work. These were later expanded into the Disquisitio Metaphysica (1644). But along with his scepticism Gassendi reserved a place for genuine scientific knowledge and enquiry, and cultivated an atomism owing much to Epicurus, and itself much in tune with the emergent materialistic science of the 17th century. Gassendi’s three volumes of commentary on Epicurus were among the works collected in the posthumous Opera Omnia of 1658.

http://www.newadvent.org/cathen/06391b.htm An introduction to Gassendi, including his philosophy

http://www.clas.ufl.edu/users/rhatch/pages/11-ResearchProjects/gassendi/index.htm A chronology of Gassendi’s life and works