Ogam (or Ogham), the ancient Celtic Tree Alphabet, is believed to have been developed very early, perhaps even before coming into use by the Druids. There is some dispute about who originated what, but we do know that Ogam has been a key element both in transcribing things of importance among the Celts (and arguably even before the Celts settled widely in Europe), and as an important divination tool. These two very different books both contain versions of the Tree Oracles, although Mountford devotes the entirety of his manuscript to the Oracles and the use of Ogam, while Monroe covers the subject(s) as part of a body of work devoted mainly to alleged Druidic practice and ritual.
In the better and more focused book, Ogam: The Celtic Oracle of the Trees, Mountford gives a comprehensive, knowledgeable, and very straightforward body of information. While he gives attention to the historic myth cycles, deities, visualization techniques, and accompanying folklore to better provide an encompassing overall picture of the nature of the enigmatic Tree Oracles, his is a book primarily dedicated to their wisdom, and to the use of Ogam in divination. To allow better understanding, Mountford also describes each sacred tree’s Celtic name, status, sounds and associations.
In many respects, Mountford treats the Ogam in much the same manner as Tarot cards, and offers different ways of "Ogamcasting" -- including different "spreads" one could use for divination readings. Interestingly enough, Mountford uses stones instead of the traditional wooden sticks, but stresses that each individual should use whatever material he or she feels comfortable with. Authentic Ogam sticks are made with wood from each of the oracle trees used if available -- or ash, if these trees do not grow in the reader’s area. (Traditionally they have the alphabetical symbol representation burned into them -- but this is not absolutely necessary). At the end of Ogam, Mountford gives sample individual readings for the different methods of divination, whether using the spread method or Ogamcasting. I highly recommend Ogam: The Celtic Oracle of the Trees to anyone with an interest in the spiritual aspects of the ancient "tree alphabet," understanding that it is much more than a means of written communication. It encompasses a whole philosophy: a system of living with and venerating the agents of nature to which the Celts assigned the highest power.
By contrast, although I found Douglas Monroe’s The Lost Books of Merlyn interesting reading at first, I began to wonder where he gathered all of his information. While he presents himself to be quite an authority on Druidic and even pre-Druidic practices, I thought it odd that I had never seen this material represented in the more scholarly books on Druidry. The source of much of Monroe’s "knowledge" is an ancient Welsh manuscript supposedly pre-dating the Celts, the Book of Pheryllt. Monroe even goes so far as to say that this Pheryllt manuscript is the re-creation of written magic and lore from the priests of drowned Atlantis. That claim aside, the Lost Books does give a poetic description of the Tree Oracles, using both the pre-Celtic system of writing called the Boibeloth, and the Ogam representations from Cad Goddeu’s "Battle of the Trees," which does exist. The rest of Monroe's book may be mumbo-jumbo, but his Oracle of the Trees is quite beautiful. Essentially, the difference between his interpretation of the Oracles and Mountford’s is a matter of eloquence. The information given is not so different. Monroe gives his story of the Ogam symbols and the original Boibeloth through a fictionalized tale loosely based on "Battle of the Trees." He details the representations in Welsh, English, and Irish (the symbols do vary, as well as the various statuses of the individual trees). These, too, were interesting, although I have no idea how authentic they are.
In fact, I did some research on the Internet regarding this Book of Pheryllt, from which Monroe draws so much of his material, and found it sharply discredited by the present authorities on the Druidic Order. Phillip Carr-Gom, who himself has been the head of the British Order, had this to say: "One of the most widely-read books on Druidry is unfortunately the worst -- Monroe’s 21 Secrets of Merlyn." I found this comment from Lisa Spangenberg, a respected Celticist: "I keep hearing references to a supposed medieval Welsh manuscript called The Book of Pherllyt. I have a suspicion that most, if not all, of these references are inspired by the truly wretched and quite idiotic book The 21 Lessons of Merlyn by Douglas Monroe... Hogwash. There is no such sixteenth century manuscript. Monroe’s recent ‘sequel’ (The Lost Books of Merlyn) is an obvious fake from the nineteenth and twentieth centuries, full of egregious factual errors and offensive sexual and racial assumptions. At best it is a piece of poorly thought out fiction; it has absolutely no scholarly value at all. Monroe clearly knows nothing about ancient Celtic practices, languages, Druids, botany, or mythology." You can check out these comments yourself at Celtic Studies Resources.
Whoa. What did Monroe do, make most of this up? If so, he has quite a sense of imagination -- or maybe just a hopeless attachment to faked "archives." Supposedly, Monroe has established his own Druidic "study center" called New Forest, somewhere in Mexico. He has no real credentials, other than teaching a Humanities course at a local Mexican college. Case closed.
So all of the spells, grimoires, recipes, invocations, etc. in The Lost Books of Merlyn are a bunch of mumbo-jumbo. He may think he is the heir to the lost wisdom of Atlantis, but apparently authorities on the subject of Druidry and Celtic history think he’s a fake. Their word’s good enough for me. True, the Tree Oracles derived from the Cad Goddeu he provides are close enough to the enigmatic Ogam representations to be useful. But the rest of the book? Apparently it has angered a lot of people, and it is clearly, without a doubt in the world, the inferior book of these two.
Anyone interested in the system of divining by way of traditional Ogam methods should read Mountford’s Ogam: The Celtic Oracle of the Trees. While I have yet to create any Ogam sticks myself, this book makes the process more than fascinating -- it makes it credible. Believable. Buy it for a friend for Christmas. And Monroe’s book? Don’t buy it. Run away! Save the money if you don’t buy Mountford’s book -- or if not, buy a model kit, a box of Legos, anything! And make sure, if you’re thinking of getting The Lost Books of Merlyn for a Christmas present, that you aren’t giving it to a real Druid.