His daughter tells us that a police agent came one day to the house, and proceeded to search the author's room.

He found a manuscript, said, "Good, that is what I am looking for," thrust it into his pocket, and went away.

Diderot did his best to recover his piece, but never succeeded.[43] A copy of it came into the hands of Naigeon, and it seems to have been retained by Malesherbes, the director of the press, out of goodwill to the author.

If it had been printed, it would certainly have cost him a sojourn in Vincennes.
We have at first some difficulty in realising how he police could know the contents of an obscure author's desk.

For one thing we have to remember that Paris, though it had been enormously increased in the days of Law and the System (1719-20), was still of a comparatively manageable size.