What is the ultimate dystopian novel

There are many, most of them obvious, but I wished to reference the little known but perhaps greatest of them all “The Iron Heel” by Jack London. Almost all have read Orwell’s Animal Farm and Nineteen Eighty-four, Gibson’s; Neuromancer, Bulgakov's; Master and Marguerita, Solzhenitsyn's; A Day In the life of Ivan Denisovich but few have gone back to the very start. I suspect FMA de Voltaire was the culprit. “London”, long before those credited, greatly, wrote perhaps the definitive dystopia. "The Iron Heel".