The Absolute, published in 2001, is the 51st book in the Animorphs series, written by K. A. Applegate. It is known to be written by Lisa Harkrader. It is the final book (fully) narrated by Marco. Published February 2001.

The books opens with Marco and Tobias in bird morph, surveying a freight train transporting tanks into the city. They are spotted and attacked by Controllers in bird of prey morph, revealing that the Yeerks now have the ability to morph after obtaining the Escafil device in the previous book. Marco and Tobias escape by stealing a tank, which they use to demolish Chapman's house before fleeing.

Back in the Hork-Bajir valley, the Animorphs speculate that the Yeerks are planning to infest the state's National Guard en masse. A personal issue is also presented in the form of Jake's depression, which affects the morale of the group. Marco also notices tension between Jake and Cassie, but does not know the reason for it, as he, Rachel, Tobias, and Ax are still unaware of Cassie's actions at the end of the previous book.

Jake decides to send Marco, Tobias, and Ax to the state capitol to warn the governor of the Yeerk plot, while he, Cassie, Rachel, and the Auxiliary Animorphs attempt to slow the Yeerks down with the usual assault tactics. Marco's team infiltrates The Gardens to acquire mallard ducks for the long-distance flight to the capitol. Here, they are again attacked by Controllers with the morphing ability, but manage to escape.

They arrive at the capitol and locate the governor in cockroach morph, eventually demorphing and revealing themselves to whom they think is the governor when he is alone (other than his wife and bodyguards). They are surprised to find out that the man to whom they reveal themselves is not the governor, but that his wife is the one they seek. The possibility of the governor being a woman had escaped Marco, Tobias, and Ax's minds. Unfortunately, her husband is a Controller, and he alerts the Yeerks. Marco, Tobias, and Ax grab the governor and race through the streets of the capitol, aided by her closest bodyguard, Collins, while being pursued by the Yeerks. Collins is injured in the shoulder with a Dracon beam, but is saved by Marco. After destroying a helicopter and a yacht, they lose their pursuers and return to the governor's mansion to explain the situation to her and Collins.

The governor and Collins (who refuses to go off duty in spite of his injury) are accepting of the danger, and the governor calls in a group of National Guardsmen who have been doing training missions in the desert for the last few weeks, and can therefore be assumed to be uninfested. Unfortunately, an infested company arrives first with the intention of kidnapping and almost certainly infesting the governor. Marco deceives them by morphing the governor, letting himself be captured by the Yeerks, and being rescued by Tobias and Ax (meanwhile, the real governor escapes, along with Collins).

Marco, Tobias, and Ax return to the Hork-Bajir valley in time to see the governor issue a televised warning about the Yeerk invasion.