Firstly, I'm pretty sure that was my first poker book, and I think its definitely worth reading.
Here's a summary of my answer:
- Question the material. Experiment with the advice,but don't trust without examining it closely.
- Splitting the book material into Subjective and Objective parts is worthwhile.
- Pay special attention to Dis-positional vs Situational perspectives.
- Vested interest of the author is important to measures of validity.
I think what is interesting here is how the answer to this question draws a lot from the format of StackExchange itself, and why it works so well.
The first question, is akin to asking Is the author (Dan Harrington) trustworthy? It's highly subjective, much like the game itself, and aside from the objective math, its predominantly about logical reasoning in the material and judgement of the authors character. There are a few other relevant factors (discussed later), but I believe these two are the most important.
By itself, the information in the book, as with most books, is part conceptual and part mathematical, both implicit and explicit. Maths is fair and provable. Concepts are often, but not always, subjective and open to discussion. There can certainly be a great deal of logic involved in theoretical explanations, so many examples are shown to have sound reasoning. The examples that don't are quickly recognized and given less importance. my advice would be, when reading, be aware of the type of material you're currently reading.
Aside from the logic of the material, the author is worthy of scrutiny. When an author publishes anything, you only need to look at what they stand to lose to understand the importance of being genuine. Dan Harrington, at the time of writing this book was at the forefront of publishing in the poker arena. Add to that his endorsements, and that he drew his living from the game itself, gives us as readers some confidence in his expertise. If the author were unknown, had no obvious vested interest in the game, then skepticism would naturally increase about the validity of the advice, and rightly so. This is also the reason I appreciate Poker.Stackexchange. More signal, less noise, and a measure of reputation.
Poker books are an unusual mix of fact and fiction, the balance of which affects our trust. Trusting the facts of the maths presented by successful people, and believing in their representation of the fictional situations they use as examples, are compelling to those learning the game. It's like being shown the inner workings of magic. These situations are stories. As players, we're story-tellers at heart. Poker techniques are like stories which are creatively brought to life by a good narrator, but if the author breaks the fabric of the underlying narrative then trust is lost and the validity along with it. This fragile mix of fiction and non-fiction, should increase our confidence in the material. Any unbalanced skew of the material toward too fictional a narrative, quickly sees the book assigned to the bargain bucket of bookstores. Discount bins are natures literary filter.
I could probably go on, but i'll just summarize a few extra things worthy of mention.
Some factors to consider when considering trustworthiness of poker material:
The reproducibility of results. A necessity in scientific validation. If the advice doesn't produce the aforementioned effects, the methods are quickly discarded as incredulous. Much the same for poker techniques. It's trial and error methodology, but it does mean that bad advice isn't used for long.
The possibility of mistakes as opposed to fraud. Maybe in practice the ideas will work for the author, but not for you. This seems to relate to a few logical fallacies, one being "False Dilemma" where the fallacy can occur by accidental omission of extra situational aspects and not by deliberately omitting them.
Does the author know what is inessential? If the material equates to the science of poker writing, editing is the art of poker writing. The author's points may be valid, but if they're not in context they can be misleading.
Lots to think about! :)