If the topic interests you, I highly recommend Karen Armstrong's book The Battle for God. She analyzes the histories of fundamentalist movements in Christianity, Judaism, and Islam, and calls out what they have in common. What emerges, to me, is that fundamentalist movements primarily are backlashes to social change that find expression in religion.
Fundamentalists are motivated by existential fear more than by devotion. They see themselves in danger of annihilation from something they think the modern world is forcing on them.
Traits common to all fundamentalist movements include --
They embrace dualistic, black-and-white, absolutist thinking. Everything and everyone is either good or evil.
They fear annihilation.
They take their values from an idealized past, either real or imagined.
They often withdraw from mainstream society to form their own communities and cultures.
They see themselves in a struggle to retake society and reinstate whatever they think the modern world is destroying.