Baudrillard is the theorist of the image that no longer refers to anything, and the one whose work reads least like philosophy and most like diagnosis.
He began as a sociologist of consumption, arguing in The System of Objects and The Consumer Society that in an affluent economy goods are bought for their position in a system of signs rather than for use — a car is a statement before it is transport. From there he pushed to the claim the work is known for: that the sign has progressively detached from any referent until representation has been replaced by simulation. The four stages he describes run from an image that reflects a reality, through one that masks it, to one that masks its absence, and finally to the simulacrum, which bears no relation to any reality at all. Hyperreality is the condition in which the model precedes and generates what it purports to describe.
The political writing follows from this and is deliberately provocative. Disneyland, he argued, exists to persuade Americans that the rest of the country is real. His notorious essays claiming the Gulf War did not take place were not a denial that people died but an argument that what was transmitted was a programmed spectacle bearing no relation to the event, consumed as a simulation by publics whose assent was thereby managed.
He is easy to dismiss and difficult to escape. Written before the internet, the account anticipated a media environment in which the copy circulates without an original, authenticity is itself a marketing category, and politics is conducted through images that no longer even claim to represent. Much contemporary writing about disinformation and virality restates his position without the citation.