How would you define the overall theme of Fight Club?
I think that one of the themes out of the book is that solidarity amongst men is extremely important to identity. It is interesting to hear the author describe his own endeavor:
...bookstores were full of books like The Joy Luck Club and The Divine Secrets of the Ya-Ya Sisterhood and How to Make an American Quilt. These were all novels that presented a social model for women to be together. But there was no novel that presented a new social model for men to share their lives.
Palahnuik's argument is an interesting one. Society cannot function without its individuals feeling some level of connection or solidarity to one another. For so long, men have had this and taken it for granted. It was almost understood that men would "retire" for cigars and brandy or meet at the local bar and hang. Over time, a social understanding has emerged that the same element is needed for women. "Girls' night out" or similar practices helps to reaffirm the need for social connections on the women side of the equation. Palahnuik's argument and a critical theme that is to emerge from it is that men have lost that element of social connection. While the idea of men beating each other up to enhance social solidarity might not be exactly what is being advocated, the theme of the work in its suggestion that men need to find comfort in one another's collective setting is a theme that emerges from the work.