The book on the Macedonian Wars belongs to the less preserved parts, but fortunately, we have access to Appian's sources Polybius or Livy.
The translation was made by Horace White; notes by Jona Lendering.
The First Macedonian War (214-205)
 [From Constantine Porphyrogenitus, The Embassies] The Romans paid no attention to Philip, the Macedonian, when he began war against them.note[214 BCE.] They were so busy about other things that they did not even think of him, for Italy was still scourged by Hannibal, the Carthaginian general, and they were at war in Africa, Carthage, and Spain, and were restoring order in Sicily. Philip himself, moved by a desire of enlarging his dominions, although he had suffered nothing whatever at the hands of the Romans, sent an embassy, the chief of which was Xenophanes, to Hannibal in Italy, proposing to aid him in Italy if he would promise to assist him in the subjugation of Greece. Hannibal agreed to this arrangement and took an oath to support it, and sent an embassy in return to receive the oath of Philip. A Roman trireme intercepted the ambassadors of both on their return and carried them to Rome. Thereupon Philip in his anger attacked Corcyra, which was in alliance with Rome.
 [From the Vatican manuscript of Cardinal Mai] The Sibylline books induced the Romans to make war against Philip by these lines:
The Macedonians boast their descent from Argive kings. Philip will be the arbiter of weal or woe to you. The elder of that name shall give rulers to cities and peoples, but the younger shall lose every honor, and shall die the subject of a western race.
[Although the Romans sent troops across the Adriatic Sea, the war against Philip was one burden too much. Fortunately for Rome, many Greek towns detested the power of Macedonia, and in 212, Rome could ally itself to the Aetolian League. The war continued.]
 [From Constantine Porphyrogenitus, The Embassies] Ambassadors from Ptolemy, king of Egypt, and with them others from Chios and Mitylene, and from Amynander, king of the Athamanes, assembled at two different times at the place where the Aetolians were accustomed to call their cities together for consultation, to compose the differences between the Romans, the Aetolians, and Philip.note[In 208 BCE.] But as Sulpiciusnote[The Roman commander Publius Sulpicius Galba.] said that it was not in his power to conclude peace, and wrote privately to the Senate that it was for the advantage of the Romans that the Aetolians should continue the war against Philip, the Senate forbade the treaty and sent 10,000 foot and 1,000 horse to assist the Aetolians.
With their help the Aetolians took Ambracia, which Philip recovered, not long afterward, on their departure. Again the ambassadors assembled and said that it was very evident that Philip and the Aetolians, by their differences, were subjecting the Greeks to servitude to the Romans, because they were accustoming the latter to make frequent attempts upon Greece. When Sulpicius rose to reply to them the crowd would not hear him, but shouted that the ambassadors had told the truth.
 [From Constantine Porphyrogenitus, The Embassies] Finally the Aetolians took the initiative and made peace with Philip by themselves without the Romans,note[206 BCE.] and messengers were sent to Rome by Philip himself and by the commander of the Roman forces in order to come to an agreement. Peace was made between them on the condition that neither party should do any injury to the friends of the other.note[205 BCE.]
This was the result of the first trial of strength between them, and neither of them believed that the treaty would be lasting, since it was not based on good-will.
The Second Macedonian War (200-197)
 [From Constantine Porphyrogenitus, The Embassies] Not long afterward Philip, having ordered a fleet to be prepared by his maritime subjects, took Samos and Chios and devastated a part of the territory of king Attalus.note[201 BCE.] He even attempted Pergamon itself, not sparing temples or sepulchers. He also ravaged Peraea,note[A part of the Carian mainland that belonged to Rhodes.] which belonged to the Rhodians, who had been promoters of the treaty of peace. With another part of his army he ravaged Attica and laid siege to Athens, as though none of these countries concerned the Romans.
It was reported also that a league had been made between Philip and Antiochus, king of Syria, to the effect that Philip should help Antiochus to conquer Egypt and Cyprus, of which [the Ptolemaic king] Ptolemy, surnamed Philopator, who was still a boy, was the ruler; and that Antiochus should help Philip to gain Cyrene, the Cyclades islands, and Ionia.
This rumor, so disquieting to all, the Rhodians communicated to Rome. After the Rhodians, ambassadors of Athens came complaining of the siege instituted by Philip. The Aetolians also had repented of their treaty, and they complained of Philip's bad faith toward them and asked to be inscribed again as allies. The Romans reproached the Aetolians for their recent defection, but they sent ambassadors to the kings ordering Antiochus not to invade Egypt, and Philip not to molest the Rhodians, or the Athenians, or Attalus, or any other ally of theirs. To them Philip made answer that it would be well if the Romans would abide by the treaty of peace they had entered into with him. Thus was the treaty dissolvednote[Summer 200 BCE.] and a Roman army hastened to Greece, Publius commanding the land forces and Lucius the fleet.note[Consul Publius Sulpicius Galba and Lucius Apustius Fullo.]