So you are trying to sell your car and you don't understand why you don't have any buyers?? Or you are trading in your car & the dealers says he can't give you the amount shown as the trade in value or "wholesale" blue book? Ah yes! The magical "Kelly Blue Book". The first thing you need to know that the values listed in the book itself are just a guide and not necessarily indicative of actual market values that a any particular car model has sold for. The job of the blue book company is to serve dealers & loan companies & banks rather than consumers. Keep in mind that in any given moment in time the actual cash value of your car could be off by thousands from the blue book values. Several years ago a consumer forced the blue book to open up its info to consumers and for a while people could see wholesale values. Later after protest by dealers & to counteract this the blue book came up with a seperate "retail" version of the book. In addition thier web site became available showing private party values, dealer retail values and supposed trade in values. The catch is dealers have hardly ever taken trade ins at "wholesale" prices. Historically for later model cars the actual trade in value of any given car was usually $2,500 below the blue book wholesale,in recent years that figure has increased to $3,500. Thus a car that had a supposed wholesale value of say $10K according to the book, the dealer will want it for $6,500 or in some cases, even less. You might ask if a dealer (book) price says my car is worth $5,600 why is the private party value only $2,300?? Why is a  value different simply because a dealer owns it? In reality it shouldn't be. But, the values are arbitrarily set that way with an explanation about the dealers costs of doing business, reconditioning expenses and the fact that people expect to negotiate a discount from the dealer or want a absurd (in the dealers opinion) trade in value against the car being sold. It;s all about "wiggle" room for the dealer. The most interesting thing that people often forget is those pesky rebates on new vehicles. Say you buy a new pickup for $20K drive it 2 years & come back to trade it in and the factory is offering a whopping $5K rebate on the new version of your truck. Now you are competeing with the factory. The dealer isn't going to give you a trade in value more than the cost of a new unit. A retail buyer offered a new $20K truck with a additional $5K off isn't goimg to buy your truck after you trade it in for 18K if a new one after rebate is $15K (Of course actual figures would  be higher, but in 2004 you actually could get a new full size pickup for $15K new, albeit it was a base truck, it did have a/c & automatic after the 5K rebate was applied). The point is once the actual book is printed if a manufacturer begins significant rebates that affect actual market values (and they do) it's too late for the book to be corrected because it's a printed medium . Next those declining values have a ripple down effect on the used cars. After all who pays the same price for a used car or truck as a new one? As an example, right now dealers are discounting late model C-5corvettes due to the release of the C-6 generation car. Factually speaking many later model C-5 models with low milage can be had in the $21-25K range even though the retail may be $35K.Why? Because those who can afford this type of car will pay the extra $5K or so to have the new model. This forces the used prices down to sell to a less affluent buyer. The next thing you know the early C-5 years ('97 & '98) take a real topple and cars that recently sold for $18K with 100K miles are now back into a more realistic price range of $8-10K less. (This has actually happened although many enthusiasts are unaware. It's very common to see a used corvette actuall sell for ten grand off the blue book retail or even more because of the economy. It's all connected. If new car prices are forced down the used cars eventually follow. As an an example I recently purchased a car from a dealer with a retail blue book of $5,600 for $1,750 cash for my daughter. Especially hit hard are the large trucks & SUVs. Some trucks that were sold for $15K used are now retaling for $7K. Imagine the rude awakening if you are trading the truck in??!! In other words be aware! You cannot rely on the blue book in this current market to set your price if you are a private retail seller. Even worse, if you are buying!! You will see alot of listings on ebay alluding to the retail blue book value when the are selling a car in very poor condition. This is absurd of course. A quick check of the fine print on the blue book web site admonishes users that blue book does not attempt to set values for cars in poor condition! (Any car with a salvage title regardless of it's current condition falls in this same catagory) Beware of "project cars" or salvage titles. A primo restoration car in near perfect restoration usually is worth about 40% to 75% less if it has a salvage title. Also, ask what state the car is titled in when buying. In some states salvage titles can be a headache. And finally note that if you are going to register a car in california make sure the car from out of state you are buying is a "50 state" car that meets California emissions, not all later model cars do. (It will be clearly marked on the emissions sticker under the hood that is madated by federal law. If that sticker is missing be suspicious!).