Very good book. Does a good job of explaining the multi-dimensional world of wine investment where you have to consider the vineyard (Grand Cru or premier cru) as well as the Producer (top tier like Rousseau, Roumier, Ponsot vs lower tier producer who might screw up what mother nature has provided), as well as the vintage (top years vs off-vintages)....then add to that the scores given by wine critics (over-rated or under-rated...potential for upgrades), the price it commands in the market, and your own personal taste...and there you have the basic building blocks by which to determine whether the wine has upside value or whether all the good news is fully priced in already.
Not necessarily a great book if you're looking for the pure investment theory side of things....for that I'd recommend "Wine Investment for portfolio diversification" by Mahesh Kumar. In this book, Sokolin doesn't dwell too much on actual portfolio theory & how Wine can be a good diversifier because of its very low correlation to stocks & bonds. Besides, as we all know in the post-Lehman world, the problem with diversification is that it vanishes when you need it most. The only thing that goes up in a falling market is correlations! Nonetheless, wine has proven to deliver great returns in bull markets and to sell off by far less than other assets when times get rough. This book is helpful for those who wish to look at Wine as an investment.