Tzvetan Todorov, a Bulgarian-French literary theorist and historian of ideas whose concerns in dozens of books ranged from fantasy in fiction to the moral consequences of colonialism, fanaticism and the Holocaust, died on Tuesday in Paris. He was 77.

The cause was multiple system atrophy, a progressive brain disorder, his son Sacha said.

A disciple of Roland Barthes, Mr. Todorov became prominent in the 1970s for his work on structuralism, a method of interpretation — influenced by cultural anthropology — that focuses on recurring patterns of thought and behavior.

He developed his study of the formal processes of storytelling into a 1973 book, “The Fantastic: A Structural Approach to a Literary Genre,” which examined the structural features in fantasy-based texts like “Arabian Nights” and Kafka’s “Metamorphosis.”

Mr. Todorov’s later books included intellectual portraits of the thinkers Benjamin Constant, Jean-Jacques Rousseau and Mikhail Bakhtin; he compiled, based on extracts from her letters, notes and diaries, the unwritten autobiography of the Russian poet Marina Tsvetayeva.