Short answers, pulled from the story.
The Roman general Sulla seized Athens and carried off the library containing the Nicomachean Ethics in the year 86 before the common era. Apellicon of Teos purchased the recovered library and attempted to restore the damaged texts using his best guesses to fill in the gaps.
Aristotle calls the ultimate goal eudaimonia, which is more accurately understood as flourishing or living well rather than simple happiness. The highest good is found in the life devoted to contemplation, which is the activity of the intellect and the most divine form of human activity.
Moral virtue is found at a mean between deficiency and excess, a concept known as the golden mean. This virtue is not theoretical knowledge but a habit developed through practice and experience, such as courage being the mean between cowardice and rashness.
Aristotle divides justice into distributive justice, which allocates goods according to the relative political standing of the parties, and restorative justice, which concerns transactions that have resulted in an imbalance. He argues that the just is a sort of mean where a judge must redistribute value so that both parties have the mean.
Andronicus of Rhodes organized the version of the Nicomachean Ethics that eventually reached Rome in the first century before the common era. The oldest surviving manuscript, the Codex Laurentianus LXXXI.11, dates only to the 10th century.