Hobbes focused on one of the most common understandings of power. In the book Leviathan he discussed that "society is the sum of individuals who carry and constitute power". Power, then, 'flows' from society to the individual, not, for instance, between individuals. The Souvereign, an important concept in Hobbes’ perspective, has the ultimate power; the Souvereign holds a monopoly over power. In other words, only the Souvereign has power. And he can exercise this power via violence and coercion.