Before the whole story begins...
When a true genius appears in the world,
you may know him by this sign, that the dunces
are all in a confederacy against him.
Johnathan Swift--"Thoughts on Various Subjects, Moral and Diverting"
Everybody else has told you who the book was written by and how they felt about it, so I think that I will try to give a brief analysis of the book and its more aparent themes. If you haven't read the book, and you don't want to ruin the surprise, don't read on.
John Kennedy Toole's opinions on the middle class society reverberate throughout every paragraph, sentence, and word of A Confederacy of Dunces. Ignatius Reilly embodies the antithesis of middle class America through his vulgar mannerisms, his elevated speech, and his general contempt for the society constructed by the middle class. His overall outlook on work magnifies the social value that we place upon it; instead of being freed from our responsibilities as laborers by the Industrial Revolution, we have enslaved ourselves with the concept that everyone must work. We cannot allow those of us who wish to be free spirits and artists to live out their dreams, or--if they should choose either of these paths--they are to be frowned upon and we should attempt to "repair" them into to conformity (asylums are mentioned several times throughout the book. Resistance to conformity to middle class society is punished by placing the offenders into the asylums; Toole suggest that those who we, as a society, consider mad may not be insane at all, but rather, they are those who cannot live with the insanity of our society).
Toole mocks the American Dream throughout the book, most noticeably through the use of minor characters. Irene Reilly, Jones, and Darlene all try desperately to meet their monetary desires, but can never seem to get a firm grip on them. Their comments and ideologies echo the societal theme that materialism is the key to happiness; in stark contrast, Mr. Levy is the paradigm of a financially successful man, yet he is miserable and depressed due to his money. Even the revolutions that Ignatius unsuccessfully led were fueled by worldly desires (I personally feel that the failures of his social revolutions were due to the fact that those who he was trying to help were only interested in their materialistic gains--not the ideals which they represented).
One other major theme which ran throughout the book was the degredation of art in America. Ignatius blasphemed, cursed, and screamed at all instances of "art" which appeared on television and at theaters. These supposed acts of art are nothing more than soulless creations of psuedo-artists for the sole purpose of appealing to the masses in order to make money; the art which once was prevalent has been snuffed out by consumerism, yet another construct of the materialistic society created by the middle class. Those artists who do stay true to themselves--such as Ignatius, and perhaps even Toole himself--are often cast aside for not being mainstream. This anti-artistic theme also parallels a slightly different anti-intellectualism theme.
And that's it. I loved this book and everything about it: its striking characters, its interesting setting, and its powerful themes. If you have read the book and you could not see past the chubby Ignatius and see the true art involved, I urge you to find a discussion group. The more you examine and analyze A Confederacy of Dunces, the more vivid, and perhaps disturbing, its story becomes.