Conversation so far:
What is The Citadel in relation to A. J. Cronin?
The Citadel is a novel by A. J. Cronin, first published in 1937, which was groundbreaking in its treatment of the contentious theme of medical ethics.
How did A. J. Cronin draw influence from his novel The Citadel?
Was A. J. Cronin's work accepted?
A. J. Cronin quickly made enemies in the medical profession, and there was a concerted effort by one group of specialists to get the novel The Citadel banned.
What did the group of specialists do to try and get A. J. Cronin's novel The Citadel banned?
Could you tell me more about the enemies of A. J. Cronin's novel The Citadel?
Is there anything else interesting about A. J. Cronin's novel The Citadel besides the enemies he made?
The novel The Citadel helped to incite the establishment of the National Health Service in the United Kingdom by exposing the inequity and incompetence of medical practice at the time.
What does the National Health Service do?
The National Health Service provides a comprehensive range of health services, free at the point of use for people ordinarily resident in the United Kingdom.

Question: Did he contribute to any other major causes?
Self-contained rewrite: Did A. J. Cronin contribute to any other major causes besides the National Health Service?