Ferdinand de Saussure's Course in General Linguistics is one of the most influential texts of the 20th-centuryan astonishing feat for what is, at heart, a series of deeply technical lectures about the structure of human languages.
The terms laid down in the Course did exactly thatand they still make up the core of linguistic terminology a full century later.
More than this, however, Saussure also highlighted the centrality of linguistic interpretation to understanding how we relate to the world, founding semiotics, or the study of signsa field whose influence on academics across the humanities and social sciences is unparalleled.