The only reason I know who J.G. Ballard is is because of Jean Baudrillard. I'm convinced it was the similarity of their names which convinced Jean to read J.G's work.
Where would you recommend I start with J.G.? I got into Baudrillard and have been meaning to go further down the train of thought.
The early works were generally overtly sci-fi, but mostly earthbound, fitting into the British New Wave of the 1960s, alongside John Brunner. The Drowning World and The Crystal World are both fantastic and unusual for the genre. The short stories are often excellent, and in my opinion some of his most original work is in this period.
The major transition came with The Atrocity Exhibition, a "cut up" novel that was more Cronenberg/Borroughs/Lynch than what came before, and magnified themes that had been emerging in his short stories. Alienation, pop culture fetishism, clinical descriptions of injuries, war (the book was originally called Love and Napalm), the horror lurking under placid suburban utopia. Crash, High-Rise etc. followed in that vein. Crash is probably the best from this period.
He wrote two autobiographical mainstream novels: Empire of the Sun is the famous one.
The late 90s/2000s novels like Super-Cannes are all rethreads of earlier stuff; the Freudian pop-psych view that we are basically animals denied the outlet of violence got a bit tired at this point. They're really well written, but I felt Ballard had lost his edge and didn't have anything insightful to add. His last novel is quite average.
So: The Atrocity Exhibition, Crash, maybe The Crystal World or the collected short stories.