I can't say I found this book disappointing - based on the author's many other books, frankly I wasn't expecting much.
Treasure literature falls into four general categories - Fact, Folklore, Fiction and Fantasy.
The best Factual books are those written by Karl von Mueller (aka, Deek Gladson), Ed Bartholomew (Jesse (Ed) Rascoe), Wayne Winters, Robert Nesmith, and a handful of others.
The dean of Folkore writers remains Prof. J. Frank Dobie. His books and articles are classics.
In the Fiction category it is difficult to beat Treasure Island, although The Treasure of the Sierra Madre (no final "s," Mr. Jameson - just as it isn't "Norstrom's") is excellent and I am partial to both Plunder of the Sun and Nostromo.
The classic Fantasy books are probably those written by Lieut. Harry Rieseberg, although F.L. Coffman's 1001 Lost, Buried and Sunken Treasures and his other works blend Fantasy with some fiction.
There really should be a fifth category - the aggregators, such as Thomas Penfield and Michael Paul Henson - but that's another topic for another day.
Back to Treasure Hunter. I simply don't believe the stories in it. However, for TN purposes I think one should concentrate on the Introduction, where Mr. Jameson states "It is important to understand that almost everything treasure recovery professionals do is illegal." This is a remarkable statement, indeed. And, in my opinion, a very wrong one.
It certainly is true there are laws regarding treasure hunting on private, state and Federal lands. Each state has its own laws, rules and regulations. Smart treasure hunters follow them. I simply cannot agree that "...the bizarre and unreasonable laws related to treasure recovery have turned honest, dedicated, and hard-working fortune hunters into outlaws."
If they are honest they don't break the law.
Finally, a seasoned professional treasure hunter ought to know salvage recovery laws have nothing to do with land finds. These are the laws of treasure trove, abandoned property, etc. Salvage relates to wet treasure, not dry.
There are many other problems with this book. I don't think one has to be a gunslinger to become a successful treasure hunter. Shootouts just aren't the order of the day. And, again, most of the yarns here stretch credibility and credulity beyond rational limits.
In the end, this book probably has far more in common with Howard Jennings' The Treasure Hunter than the author intended. And that is not intended to be a compliment.