Here are the answers to your questions about "The Third Level" by Jack Finney:
1. Jack Finney
2. John Finney
3. Not applicable, his given name was John Finney
4. Science fiction and thrillers
5. A pleasant wish or fantasy that allows one to temporarily escape from or forget the pressures and unhappiness of reality
6. Human tendency for escapism due to the harsh realities of the present
7. In a serious manner
8. A human tendency to escape from the harsh realities of the present to past happy times
9. Charles' finding of the Third Level and wish to visit Galesburg, Illinois represented an escapist fantasy
10. Louisa