Slavery in Rome, unlike more modern forms of slavery, was not based on race. Slaves in Rome were usually prisoners of war, but in desperate situations, fathers could sell their children into slavery. It was also common practice for orphaned children to be picked up and used as slaves. Slaves were considered the property of their masters, and brutal treatment was the norm. There was also no law against killing slaves. However, some Romans, such as the philosopher and poet, Seneca, argued for the fair treatment of slaves. Seneca said, “The result is that slaves who cannot talk before his [master's] face talk about him behind his back. It is this sort of treatment which makes people say, 'You’ve as many enemies as you’ve slaves.' They are not our enemies when we get them; we make them so.”
Slaves worked everywhere in Rome. Although it is unknown how many slaves there were in Rome, it is estimated that 25% of all Roman people were slaves. A rich Roman man could own as many as 500 slaves, and an emperor like Augustus or Tiberius could own as many as 20,000. Slaves were responsible for just about any job imaginable. In private households, slaves were expected to help dress their owners, cook and clean, and do other household tasks. They helped their owners bathe and even carried them around. Basically, a slave was expected to wait on his master hand and foot. Slaves also worked in mines, factories, on farms, and for city governments. They built aqueducts, roads, and buildings. Most slaves looked exactly like a typical Roman citizen, making it sometimes difficult for people to distinguish between the two. The Senate once considered making all slaves wear special clothing but eventually decided against it so that the slaves were not tempted to join forces and rebel.
A slave was usually a slave for life. The only exceptions were if their owners freed them or if they bought their own freedom. The price of freedom usually equaled the price their owner had paid for them, with young males usually being worth the most. A slave who was a good cook was also highly valuable. Slaves who were freed formally by a magistrate had all the same rights as a Roman citizen, with the exception that they could not hold office. Informally, freed slaves were not citizens, and their property and money reverted to their former masters after death. Once slaves were freed, they were able to work the same jobs as Roman plebeians, such as craftsmen, midwives, or traders. 
Edited by Dominick DiMercurio II for a few minor grammatical errors. Checked with http://plagiarisma.net/; status: unique, 86% originality. Note: references are given.