The most obvious and prominent theme in Novel Without a Name is how the horrors of war can change the mentality and perspective of soldiers. The protagonist and his two friends start out as decorated young soldiers in the North Vietnamese military force (People's Army of Vietnam), but one quickly succumbs to complete psychosis and is institutionalized. The experience of Bien literally being "driven to madness" is symbolic of how war can alter the psychological makeup of men.

Another theme is loyalty. Luong is the most career-driven and passionate about the cause of the Party and is the personification of military and political loyalty. The protagonist, Quan, is the personification of the everyday man who is torn between remaining loyal to his comrades and the revolutionary ideals instilled in him, and the realities of war and bureaucracy. There is also a sense of personal loyalty to each other. Quan is tasked with freeing Bien by Luong. Despite the brutality of war and their differing perspectives and personalities, Bien and Luong try to remain loyal to each other. His friendship with Luong is also one of the reasons Bien finds it difficult to turn his back on the Party.

Lastly, the theme of humanity, or commonality among people of different cultures, is evident in the last section of the book. When Bien realizes that he doesn't hate Americans and that the young American soldiers were pawns of the larger politics at play just like him, he regains his sense of humanity.