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 (171-168)
 [At the beginning of the war, in 171 BCE, king Perseus of Macedonia defeated the Romans near Callinicus.]
[From Constantine Porphyrogenitus, The Embassies] After his victory Perseus, either to make sport of Crassus,note[Consul Publius Licinius Crassus.] and by way of joke, or to test his present state of mind, or fearing the power and resources of the Romans, or for some other reason, sent messengers to him to treat for peace, and promised to make many concessions which his father, Philip, had refused. In this promise he seemed to be rather joking with him and testing him. But Crassus replied that it would not be worthy of the dignity of the Roman people to come to terms with him unless he should surrender Macedonia and himself to them. Being ashamed that the Romans were the first to retreat, Crassus called an assembly, in which he praised the Thessalians for their brave conduct in the catastrophe, and falsely accused the Aetolians and the other Greeks of being the first to fly; and these men he sent to Rome.
 [From the Suda] Both armies employed the rest of the summer in collecting corn, Perseus threshing in the fields and the Romans in their camp.
[In 169, the Romans invaded Macedonia, winning several engagements.]
 [From the Suda] Henote[Consul Quintus Marcius Philippus; 169 BCE.] was foremost in labor, although sixty years of age and very corpulent.
 [From the Suda] Then somebody ran to Perseus, while he was refreshing himself with a bath, and told him.note[That the Romans were approaching.] He sprang out of the water, exclaiming that he had been captured before the battle.
 [From the Peiresc manuscript] Perseus, having already gradually plucked up courage after his flight, wickedly put to death Nicias and Andronicus, whom he had sent with orders to throw his money into the sea and to burn his ships; because after the ships and money had been saved he knew that they were witnesses of his disgraceful panic and might tell others of it. And from that time, by a sudden change, he became cruel and reckless toward everybody. Nor did he show any soundness or wisdom of judgment thereafter, but he, who had before been most persuasive in council and shrewd in calculation and courageous in battle, barring his inexperience, when fortune began to change became suddenly and unaccountably timid and imprudent, as well as changeable and maladroit in all things. Thus we see many who lose their usual discretion when reverses come.