This is one of those books that was written about 100 years ago but which turns your head in terms of how society and high society works. It answers some questions on why people wear luxuries and the rules of polite society.
If you get this book, consider also reading The Theory of the Leisure Class (Oxford World's Classics). At times when reading both the Conspicuous Consumption and The Theory of the Liesure Class you might think that the books are very outmoded but at the same time you recognize that there is a strata of society that still behaves by some of these rules today.
Definitely, if you're looking to understand the finer nuances of high society, your education is not complete until you read both Conspicious Consumption and the Theory of the Liesure Class.
I was studying the behavior of royalty in ancient societies and wanted to do a bit of research into the parallels of modern Western society -- lets just say I received quite a bit of insight from these two works. Consider them.