Tom climbs out the window to get a piece of paper that seems important to him.
The harrowing description of Tom's experiences once he is out on the ledge would make it seem that he must have been crazy to have gone out there in the first place. But it doesn't seem so crazy to Tom while he is still safe inside his apartment and is merely considering it.
To simply go out and get his paper was an easy task—he could be back here with it in less than two minutes—and he knew he wasn't deceiving himself. The ledge, he saw, measuring it with his eye, was about as wide as the length of his shoe, and perfectly flat. And every fifth row of brick in the face of the building, he remembered—leaning out, he verified this—was indented half an inch, enough for the tips of his fingers, enough to maintain balance easily. It occurred to him that if this ledge and wall were only a yard above ground—as he knelt at the window staring out, this thought was the final confirmation of his intention—he could move along the ledge indefinitely.
The story is really about the fear of heights: acrophobia. The reader becomes involved in the story because he or she identifies with Tom's fear of falling. Tom knows that if he thinks about falling he is likely to fall. He is struggling with himself the whole time he is out there on the ledge. While he is still looking out the window of his apartment he can't foresee what thoughts, feelings, and impulses he will have to cope with, along with the sheer physical difficulties involved in picking up the precious piece of yellow paper once he gets to it.
He has to walk with his body pressed tightly against the wall. He is almost hugging the brick building. Then, when he gets to the paper, it is impossible to bend over and pick it up. He has to put himself in an awkward, painful and unsustainable position with his knees spread and a large part of his lower body extended precariously out over the ledge. All this time he has clung to his resolution not to look down. He knows that the sight of the street eleven floors below him will cause vertigo, which could be fatal. But he finds that he is not going to be able to get a real grip on the yellow paper unless he looks down at it—if only for a moment. Otherwise, there is a good chance that he might only detach it from where it is securely wedged and have it fly off into the night. Jack Finney saves the description of the sight of Manhattan at night from eleven floors up until this point. Then:
He saw, in that instant, the Loew's theater sign, blocks ahead past Fiftieth Street; the miles of traffic signals, all green now; the lights of cars and street lamps; countless neon signs; and the moving black dots of people. And a violent instantaneous explosion of absolute terror roared through him.
This is excellent description. Manhattan truly is an awesome sight. It might be called one of the wonders of the modern world. The part about the traffic signals all synchronized to change colors at the same time is a nice touch. When the signals all suddenly change from green to red, it should have a dizzying effect on Tom as well as on the reader.
"Contents of the Dead Man's Pocket" is an ingenious story. Tom learns a valuable lesson. The worst thing that ever happened to him is the best thing that ever happened to him. He learns what is really valuable in life and what is illusory.