Sometimes it's truly weird how Hollywood cranks out a hit.  Howard Hawks' film adaptation of the notoriously convoluted and confusing Raymond Chandler novel was actually completed, and in the can in 1945. But then Warner suddenly realized, with the war coming to an end, they had to rush all their WAR themed movies out the door RIGHT NOW while there was still a market for them!  So "The Big Sleep" was put on the shelf.

And THAT gave Lauren Bacall's agent a chance to lobby with Jack Warner.  To wit: The film should be reshot and reedited to give Bacall more screen time with Bogart, along with new dialog geared at reprising their fiery chemistry from, "To Have and Have Not" (1944).  The result is truly amazing of course; even iconic.  It probably helped that the Bacall/Bogart affair going on during the 1945 shoot had turned into the Bacall/Bogart marriage by 1946!