Caesar organized his commentaries into three separate books, at that time written on individual
scrolls. Each book is subdivided into numbered paragraphs. The books cover a two-year period discussing the Roman Civil War during 49 and 48 BC.
Book I Written as a narrative, the book begins with the expiration of Caesar's term as governor of Gaul and the party dominating the
Roman Senate ordering him to return to the city to face charges of misconduct and possible execution. Caesar explains how he was wronged by Pompeius and his cohorts, who refused to permit him the
triumph that was traditionally permitted to victorious generals. He proceeds with his army to invade
Italy from Gaul. Pompeius attempts to raise an army in southern Italy, but is forced to retreat with the army to Greece. Caesar continually points to his efforts to reach an accommodation with Pompeius, and attempts to portray Pompeius as a jealous man only interested in perpetuating a rule in which he and his inner circle control the Republic.
Book II Caesar's lieutenant
Gaius Trebonius besieges
Massilia. After a long siege, the Massilians finally surrender to Caesar, who shows his typical leniency to the vanquished.
Curio sets out for Africa and establishes camp near Utica. He routs the troops of
Publius Attius Varus, and the
Numidian King
Juba sends reinforcements to Varus. Curio is overly confident; his poor decision-making leads to his army being trapped and slaughtered by the Numidians. Juba takes several Roman senators captive.
Book III Caesar and his army follow Pompeius across the
Adriatic Sea to Greece after a mop up operation in Italy and in Spain. In Greece Pompeius initially has the stronger position, with more troops, controlling many of the strategic areas. Caesar writes a lengthy monologue about the superiority of his army of elite veterans of the
pacification of Gaul, and dismisses Pompeius' tactics and the strength of his army. He points out that Pompeius' army was drawn largely from the provinces and was poorly trained. After Caesar successfully outmanoeuvred Pompeius's army in the eastern Balkans, Pompeius and his army gradually fall back into
Macedonia. Caesar then writes another monologue portraying Pompeius as a coward because of his refusal to make a stand against Caesar, whose army was beginning to have supply problems, and pointed to Scipio as the primary obstacle to peace. Caesar describes Scipio as a maniacal and untrustworthy but weak villain concerned only with destroying Caesar. Scipio raises a personal army of his own from his provinces in
Asia Minor and moves to reinforce Pompeius. The book climaxes with the
Battle of Pharsalus in June 48. The lengthy battle and siege resulted in a decisive victory by Caesar's army. Pompeius and his cohorts flee to other areas of the Republic in an attempt to reverse their fortunes. Caesar then leads his army across the
Mediterranean Sea in pursuit of Pompeius, who had landed in
Egypt. There Pompeius was murdered, according to Caesar, by the Egyptians. Caesar ends the book with an epilogue on the Egyptians' lack of justification for killing Pompeius. He then proceeds to explain his reasoning for occupying Egypt with his army, using a succession crisis among the Egyptian royal family as his pretence. The Egyptians resisted and Caesar seized the
Pharos. The book ended with the line "Haec initia belli Alexandrini fuerunt." ("These things were the beginning of the Alexandrian war"). The events of the book were followed by the books
Alexandrian,
African and
Hispanic wars, written most likely by officers of Caesar's armies. ==Criticism and revival==