“The source of Man’s unhappiness is his ignorance of Nature.”D’Holbach believed that the misery he saw in mankind around him was caused by religion and its superstitious beliefs – that there was a God who controlled destiny and would reward or punish individuals. The System of Nature was written to replace these delusions with a schema of understanding based solely on the physical workings of nature. “Let Man study this nature, let him learn her laws, contemplate her energies.” For d’Holbach the soul is only the physical body, understood from a certain point of view, which dies when the body dies. All the events and the nature of the world can be understood in terms of the motion and properties of matter; even the tiniest causes contribute to huge events – a simple change in the diet of an Emperor (or some other such insignificant cause), he suggests might have been capable of “saving kingdoms.” For him, nature’s laws are fixed and necessary, and if Man wants to find happiness it is best to accept this – if governments want to rule wisely they should base themselves on this principle. Man’s fear of death and desire for immortality should be resisted and those in power should not be allowed to play upon these passions.Clinamen Press has issued the book with a fully modernized text and a newly commissioned introduction by Michael Bush. Recently retired from Manchester University, where he was a reader in History, his previous works include the very successful What is Love? Richard Carlile’s Philosophy of Sex for Verso (1998) and Pilgrimage of Grace: a Study of the Rebel Armies of October 1536 (1996). He is a keen collector of rare books, specializing in radical authors.