Most people only look at the last column of figures in the book. What do all the numbers represent?

Most people who get access to the Auto Dealers Guide don’t understand the numbers and columns, nor do they read the the guidelines at the beginning of the book, which are actually very important. There is a general misunderstanding of what the columns of figures in the book mean: The Trade/Retail values in the 'book' are meant to indicate the following: 

(T) TRADE: This is the approximate price the book suggests a dealer should pay for a vehicle as a trade-in, subject to the vehicle having average mileage (these averages can be found on the last page of the book) and then any amounts for reconditioning to get the vehicle into showroom condition must still be deducted. Plus allowances must be made for local/regional fluctuations in popularity and supply/demand variations. 

(R) RETAIL: This is the suggested price a dealer should sell a vehicle for, subject to mileage and condition, supply and demand, local fluctuations etc. 

There are a further two columns on each page:

H = The highest price achieved nationally on this specific product for this month 
L = The lowest price achieved nationally on this specific product for this month 
No: The number of units sold nationally of this specific product for this month. 
This information helps to establish desirability and trends. For example if only one or 2 of the specific model have been sold it might indicate that this is a less popular model and therefore not command a high resale value.

The column on the extreme left of the page is the original new price for that product in that year. This helps to determine how fast/slowly resale values have changed.

Are there any other factors which affect book values? 

There are many variables in determining desirability of a particular vehicle. Demand for a vehicle can also change rapidly. For example, the Hyundai range of cars' saw their resale value tumbling when that company temporarily closed its doors in 1995. When there is a big fuel price hike, most cars that are considered gas guzzlers will see their resale values taking a dive.

Can you simplify into one sentence why my car doesn't sell?

There are only two reasons a vehicle doesn't sell. One is PRICE - the other is CONDITION. So, if you are selling your car and you know it is immaculate in every way, and no-one answers your advert, you are asking too much (on that given day). Try again tomorrow or next week. But if, after three weeks, it is still unsold, and you are still convinced that CONDITION is not an issue, it is time to drop the price.

THE DEFINITION OF THE MARKET VALUE OF ANY PRODUCT OR SERVICE IS HOW MUCH YOU CAN GET FOR IT IN CASH ON ANY GIVEN DAY .