Lucan's "Pharsalia" (or, "Civil War", as many scholars now prefer to call it) was written approximately a century after the events it chronicles took place.
Lucan was born into a prominent Roman family (Seneca the Elder was his grandfather, and Seneca the Younger his uncle), and seems to have befriended the young Emperor Nero at an early age. He was for several years a poet of some prominence in the Emperor's court, and it is during this period that the "Civil War"/"Pharsalia" was probably begun. However, Nero and Lucan's friendship evidently soured, and in A.D. 65 Lucan joined Calpurnius Piso's conspiracy to overthrow Nero. When the conspiracy was discovered, Lucan was given the option of suicide or death; he chose suicide, and recited several lines of his poetry while he died (possibly Book III, l. 700-712).
Lucan's "Pharsalia" was left (probably) unfinished upon his death, coincidentally breaking off at almost the exact same point where Julius Caesar broke off in his commentary "On the Civil War". Ten books are extant; no one knows how many more Lucan planned, but two to six more books (possibly taking the story as far as Caesar's assassination in B.C. 46) seem a reasonable estimate.
It should be noted that, as history, Lucan's work is far from being scrupulously accurate, frequently ignoring historical fact for the benefit of drama and rhetoric. For this reason, it should not be read as a reliable account of the Roman Civil War. However, as a work of poetic literature, it has few rivals; its powerful depiction of civil war and its consequences have haunted readers for centuries, and prompted many Medieval and Renaissance poets to regard Lucan among the ranks of Homer, Virgil, and Ovid.
Duff, J.D.: "Lucan: The Civil War" (Loeb Classics Library,London, 1928). Latin text with English translation.
Braund, Susan H.: "Lucan: Civil War" (Oxford University Press,Oxford, 1992). NOTE: Highly Recommended Translation!
Fuller, J.F.C.: "Julius Caesar — Man, Soldier, and Tyrant"(DaCapo Press, New York, 1965)
Gardner, Jane F. (Trans.): "Caesar: The Civil War" (PenguinClassics, London, 1967). Also contains "The Alexandrian War","The African War", and "The Spanish War", all anonymous.
Getzer, Matthias: "Caesar, Politician and Statesman" (HarvardUniversity Press, Cambridge MA, 1968).
Holmes, T. Rice: "The Roman Republic" (Oxford University Press,Oxford, 1923). 3 Volumes.