This well produced and well presented overview of the Welsh legends of Merlin, the famous mythical Wizard, is coherent and consistent; It's also totally bonkers.
When writing a history of mythic figures and times,the author has a choice of a dry reportage of odd long dead beliefs or an enthusiastic embracing of the implied magic and wisdom the myths could be seen as representing. Michael Dames is solidly in the latter camp.
It is perfectly possible to report on such things while taking a middle way between the two extremes. For example, Robert MacFarlane'e "The Wild Places" has :"To travel somewhere like..Sutton Hoo...is to find...beliefs expressed here, you think, which might be learned from.A sense of orientation, perhaps, or connection."(p172)
In many ways, a more measured tone, like MacFarlanes's is more instuctive than what can seem to be an uncritical assumption that the wonder tales from ancient times have an actual and literal magic, a view Dames more or less states again and again.
"Merlin and Wales" contains many assertions which are interesting and eye-catching, but Dames doesn't try to support these assertions, and so they become merely bald opinions.Wishful thinking even : e.g. "Who was Vivien? Some scholars derive her name from chwifleian....a term of endearment used by Merlin..when addressing his twin sister...It was therefore with his thinly disgusied sister that he incestuously reunited." This is a pretty large leap of logic, supported by "some scholars" who remain totally anonymous.
Dames does have an irritating habit of conflating obviously different figures, Bran and Arthur for example. This reaches a absurd head on page 159 when all three Bards in a contest at Caerleon are revealed to be separate versions of Merlin.
Having said all this, the book is easily digestible and contains loads of interesting bits, discussions of Glass in Celtic legend, Modern Day survivals, Ghost Dogs etc etc. And the illustrations are all excellent.