The book deals primarily with errors in the way the coins are manufactured. As an authenticator, I was trained to look at the design last. The least important element is the design - also it is impossible to KNOW the correct design for every series ever made.
So I was taught to first check the physical scientific parameters of the coin. The data you need to start with are the alloy used, standard tolerances and the method of manufacture used. This is readily available and easily memorized for most coins you will ever authenticate.
Start with the simple questions first.
1. Is the coin magnetic? If the coin was made with a standard alloy including silver greater than 20% it will NOT be magnetic. Many early numismatic forgeries were made with nickel because it was cheap could be struck easily and it can be artificially toned to resemble silver. It also rings (tone and duration are off but many people do not notice). Iron and nickel are both have magnetic properties and will respond to a magnet. Start with a simple iron magnet.
2. Weight, diameter and most importantly density are the next most important parameters. Each coin series ever made had some standards. Some coins have high levels of tolerance others low. You need to do some research to determine the range. Modern coins often have published tolerance levels. If you are unsure, it is best to think of how the coins were used in commerce. For the 8 Reales these coins were essentially bulk silver. The loss of 5% of the metal weight stopped such coins from circulating at face value in the early US. A deviation in weight can condemn a coin as fraudulent as can a deviation in density.
3. The next step is to evaluate how the coin was made. For this you need to know what the surfaces look like depending on how a coin was made. A casting has one look and a struck coin another. You need to be able to tell the difference even if it is worn, polished or artificially aged. Experience is the best teacher so look at coins of known origin. Always look with a 10-30X loupe until you become comfortable with the differences in texture, stria and what die breaks look like. Very few mints ever cast their coins and you need to know which mints and when.
4. If the coin was properly manufactured, you can move onto how was the die prepared. You need to read about and study the processes used to make dies - hub, punch, engraving and the various transfer technologies used by forgers. These all have a starting date based on when the technology was used. A genuine Portrait 8R was never made using hubbed dies, but counterfeit types were.
5. When reviewing how a coin in hand was made follow one principle - no coin could possibly be made before the technology that was used was invented. Here you need to understand when technologies were introduced. Most of these are covered in my book. They are critical because you can distinguish old from new and appropriate from inappropriate methods this way.
6. The next step is the design of the coin itself. You only need this step if the preceding ones all confirm that the coin MAY be genuine. I usually rely on graded examples of coins but with some caution. Not all graded coins are in fact genuine so you need to gather numerous examples from all of the top tier grading services PCGS (basically for US coins
- world coins like 8Rs are iffy), NGC, ANACS (great for authenticity in particular when Mike Fahey was involved) and ICG (best for world coins generally).
7. The last step is XRF or other advanced techniques. This is a last resort only needed very rarely.
This is the process I have used for about 50 years and it works. The first 5 steps take a few minutes at most. The 6th an hour or so and the 7th can take weeks. This is why the 30 seconds allowed for authentication by most TPG
's will never work.