Unfortunately, this was not to be. Browsing through the book, I found that it contains many errors and misleading statements. And these were only those detected by me from the (small) set of entries of which I had some prior knowledge.
One of the most glaring series of errors occurs in the entry Tetragrammatron. The entry reads (with internal formatting suppressed):
In the kabalah, this is the term for the four-letter name of God. In effect, it is the name of a Name. It varies from text to text. Some versions are JHVH, IHVH, JHWH, YHVH and YHWH. Since these are too sacred to be spoken outloud, the word `Adoni' is used when the name is spoken. This has led to a serious misunderstanding, since in Hebrew texts only the vowels of Adoni (or of `Elohim' - this makes it more confusing) are printed. Thus are produced the reconstructions Yahweh, Jehova, etc.
There's so much wrong with this entry that I'm not sure where to start. I'm going to refrain from pointing out the many minor errors, such as that the term "tetragrammatron" isn't actually connected to kabalah. There's no circumstance where only the vowels are printed. I'm not completely sure where Randi got this idea or what statement that this was based on. The most obvious is that in Hebrew generally only consonants are printed. It is possible that somewhere Randi got vowels confused with consonants and then thought it was something which applied only to the four letter name. The other likely possibility is that Randi was confused by the practice that, on the occasions when something is printed with vowels (such as prayer books and certain religious texts), sometimes the four letter name is printed with the correct consonants but using the vowels from Adoni. However, this practice is not the root of the vowelization in either "Yahweh" or "Jehovah."
This is not the only severe error. The entry for the Necronomicon reads:
Several additions of this grimoire have appeared. Said to have been first published in about AD 730, in Arabic, as Al Azif, by Abdul Alhazred, an English translation is attributed to John Dee. It relates powerful formulas for calling up dangerous demigods and demons who are dedicated to destroying mankind.It is a bit surprising that a nominally skeptical work would discuss the Necronomicon without mentioning that it is a completely fictional work. The Necronomicon was originally written about by H.P. Lovecraft in his horror writing in the 1920s and 30s. It is in his explicitly fictional universe that all the details above are correct. Since Lovecraft, various hoax Necronomicons have been written, but those are all very much modern creations. While this is an error primarily of omission rather than commission it is a massive mistake which makes one wonder how much attention Randi has paid to the subject.
These are not the only entries with errors. There are misleading statements about the doctrines of Christian Science, and there are claims that are so wrong that two-minutes of fact checking would find them. For example, Randi claims that Cotton Mather presided over the Salem Witch Trials.
All these errors I found from browsing through the book for about an hour. There are many entries about which I know little or nothing and I have made no effort to check the accuracy of these entries.
There are serious pragmatic and ethical concerns with this sort of sloppiness. Pragmatically, there are three major issues: First, a moderately credulous individual might pick up this book, read through it and react against skepticism as a result of seeing such a major spokesperson of skepticism engaging in such intellectual laziness. Second, a skeptic might read the book, and rely on the incorrect information for later use and thus be caught out in a debate or discussion. Third, it is common for members of fringe groups to accuse skeptics of not taking the time to understand what they are analyzing. This gives unfortunate weight to that charge.
There are three ethical problems: Most seriously, readers expect when they buy a book by James Randi to buy a book that is accurate and has been subject to minimal fact-checking. It does a disservice to readers to sell them such poorly researched material. Second, Randi and the skeptical movement as a whole have repeatedly and correctly criticized various fringe groups for engaging in poor research and outright sloppiness. It is thus the height of hypocrisy to engage in the same behavior. Third, it is in general unethical to promote falsehoods and misunderstandings.
I'm also disturbed that I can find little discussion on the internet about the flaws in this book. The skeptical movement cannot be skeptical of others and then turn a blind eye to the flaws of their own. That's not skepticism. That's tribalism.