If you've heard of this book, there's probably little new information I can offer you in this review - the great strength of The Jungle is that it is what it is without any pretensions of being something else. What it is is a muckracker novel - a novel meant to shock the public into rethinking a social issue. It's an expose in the shape of fiction.
Specifically, The Jungle begins as an expose on the meat-packing industry in Chicago, noth in terms of the way it treated it's employees, and the way it treated it's customers (an example - he describes a man falling into a cooking vat, and, since it was too difficult to fish him out, having him processed into pure leaf lard). The book was heavily researched, and carefully constructed to disgust, horrify, and shame the reader.
And as an expose, it's extremely effective. It's been 100 years since this book was written, and I hardly want to eat meat anymore.
What was interesting to me, however, was that he DID actually pay attention to the characters as well. Having read 10 Days in a Madhouse earlier this year, I was ready to see the characters as a great mass, but the greatest strength of this book, for me, was that you actually felt the feelings of teh characters. At the beginning Jurgis, the main character arrives in America, and discovers all the nasty, dishonest cruelty of the American capitalist system, and you really, deeply want him to succeed. And then, slowly, carefully, Sinclair destroys Jurgis, bit by unavoidable bit, until he becomes as ugly as the ugliest member of the machine, until he becomes the sort of cheat who was his nemesis at the beginning of the book. The brutality of the world he lives in is real because Sinclair allows him to be human, to be damaged in the way a real soul would be damaged.
The books wasn't perfect - it WAS a polemic. It had some moments in it that had the stink of preaching. But, nonetheless, at the end I was left wishing books like this were written today.