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 Third Macedonian War (Cont'd)
 [From Constantine Porphyrogenitus, The Embassies] The Rhodians sent ambassadors to Marcius to congratulate him on the state of affairs in his war with Perseus. Marcius advised the ambassadors to persuade the Rhodians to send legates to Rome to bring about peace between the Romans and Perseus. When the Rhodians heard these things they changed their minds, thinking that the affairs of Perseus were not in such bad shape, for they could not imagine that Marcius would have given this advice without the concurrence of the Romans. But he did this and many other things on his own motion, by reason of cowardice. The Rhodians nevertheless sent ambassadors to Rome and others to Marcius.
 [From the Peiresc manuscript] Genthius, king of a tribe of Illyrians bordering on Macedonia, having formed an alliance with Perseus in consideration of 300 talents, of which he had received a part down, made an attack upon Roman Illyria,note and when the Romans sent Perpenna and Petilius as ambassadors to inquire about it, he put them in chains. When Perseus learned this he decided not to pay the rest of the money, thinking that now the Romans would make war on him for this outrage. He also sent legates to the Getae on the other side of the Danube, and he offered money to Eumenes if he would come over to his side, or negotiate for him a peace with Rome, or help neither party in the contest. He hoped either that Eumenes would do some one of these things, which could not be kept secret from the Romans, or that he should cause Eumenes to be suspected by the very attempt. Eumenes refused to come over to his side, and he demanded 1,500 talents for negotiating a peace, or 1,000 for remaining neutral.
But now Perseus, learning that 10,000 foot and as many horse were coming to him as mercenaries from the Getae, began forthwith to despise Eumenes, and said that he would pay nothing for his neutrality, for that would be a disgrace to both of them, but for negotiating a peace he would not fail to pay, and would deposit the money in Samothrace until the treaty was concluded, so fickle and penurious in all matters had he become in his infatuation. Nevertheless, one of the things that he hoped for took place: Eumenes fell under suspicion at Rome.
 [From the Peiresc manuscript] When the Getae had crossed the Danube, it was claimed that there was due to Cloelius, their leader, 1,000 gold staters and, also, ten to each horseman and five to each foot-soldier, the whole amounting to a little over 150,000 pieces of gold. Perseus sent messengers to them bearing military cloaks, gold necklaces, and horses for the officers, and 10,000 staters. When he was not far from their camp he sent for Cloelius. The latter asked the messengers whether they had brought the gold, and when he learned that they had not, he ordered them to go back to Perseus. When Perseus learned this, he was again misled by his evil genius, and complained among his friends of the fickleness and bad faith of the Getae, and pretended to be afraid to receive 20,000 of them in his camp. He said that he could hardly subdue 10,000 of them if they should rebel.
 [From the Peiresc manuscript] While saying these things to his friends, he offered other fictions to the Getae and asked for half of their force, promising to give them the gold that he had on hand - so inconsistent was he, and so anxious about the money that he had ordered to be thrown into the sea a little while before. Cloelius, seeing the messengers returning, asked in a loud voice whether they had brought the gold, and when they wanted to talk about something else he ordered them to speak of the gold first. When he learned that they did not have it, he led his army home without waiting to hear another word from them. Thus Perseus deprived himself of this powerful force of auxiliaries, which had opportunely arrived. He was so foolish, also, that while wintering with a large army at Phila he made no incursion into Thessaly, which furnished supplies to the Romans, but sent a force to Ionia to prevent the bringing of supplies to them from that quarter.
[Appian's description of the battle of Pydna, in which consul Lucius Aemilius Paullus defeated king Pydna, is lost. This battle, on 22 June 168, decided the war: Macedonia was cut into four parts, and was later added to the Roman empire as a province.]
 [From the Peiresc manuscript] Some divinity was jealous of the prosperity of Paullus when he had reached such a pinnacle of fortune. Of his four sons he gave the two elder, Maximus and Scipio,note for adoption into other families. The two younger ones died, one of them three days before his triumph and the other five days after it.
Paullus alluded to this among other things in his address to the people. When he came to the forum to give an account of his doings, according to the custom of generals, he said, "I sailed from Brundusium to Corcyra in one day. Five days I was on the road from Corcyra to Delphi, where I sacrificed to the god. In five days more I arrived in Thessaly and took command of the army. Fifteen days later I overthrew Perseus and conquered Macedonia. All these strokes of good fortune coming so rapidly led me to fear the approach of some calamity to the army or to you. When the army was made safe, I feared for you on account of the invidiousness of fate. Now that the calamity falls upon me, in the sudden loss of my two sons, I am the most unfortunate of men for myself, but free from anxiety as to you."
Having spoken thus, Paullus became the object of universal admiration, and commiseration on account of his children; and he died not long after.