Lucretius poem On the Nature of Things" combines a scientific & philosophical treatise with some of the greatest poetry ever written. With intense moral fervour he demonstrates to humanity that in death there is nothing to fear since the soul is mortal & the world & everything in it is governed by the mechanical laws of nature & not by gods; & that by believing this men can live in peace of mind & happiness. He bases this on the atomic theory expounded by the Greek philosopher Epicurus & continues with an examination of sensation sex cosmology meteorology & geology all of these subjects made more attractive by the poetry with which he illustrates them."