first century Rome in a way that no other surviving text does. Each book of the Natural History covers a different topic, and the work is meant to cover every topic. Given the organization of the work, it is clear that it was meant to be a reference resource. Even modern scholars will sometimes compare an unknown object mentioned in a different ancient text with the objects described by Pliny and make comparisons. Modern scholars are also able to use Natural History to understand the traditions, fantasies, and prejudices in Ancient Rome. Some people have said that certain prejudices that have been prevalent throughout western history (such as a stigma around menstruation) were spread by Natural History. The work became a model for all later encyclopedias in terms of the breadth of subject matter examined, the need to reference original authors, and a comprehensive index list of the contents. It is the only work by Pliny to have survived, and the last that he published, lacking a final revision at his sudden and unexpected death in the AD 79 eruption of Mount Vesuvius. Death Pliny, who had been appointed praefectus classis in the Roman navy by Vespasian, was stationed with the fleet at Misenum at the time of the eruption of Mount Vesuvius. He organized and led a rescue mission upon receiving a message from his friend Rectina, who had been left stranded in Stabiae during the eruption. Pliny boarded one of several galleys that he dispatched across the Gulf of Naples to Stabiae. As Pliny's vessel approached the shore near Herculaneum, cinders and pumice began to fall on it. The helmsman advised turning back, to which Pliny replied, "Fortune favours the bold; steer to where Pomponianus is." Upon reaching Stabiae, they found Senator Pomponianus, they had supper and Pliny went to sleep that night while his company were agitated to take rest. Early the next day, he woke up to falling stones and ashes all over the place and probably, earthquake. That same time, they decided to flee to the fields with pillows on their heads as defense to the falling calcined stones and cinders rather than stay under the shaking walls and roofs. They rushed to the shore and found the sea waves running high and boisterous. The group fled when a plume of hot toxic gases engulfed them. Pliny, a corpulent man who suffered from a chronic