Bob,
I think Paul Turner sums it up perfectly on Amazon:
"I got the impression that the authors are unfamiliar with the majority of courses reviewed and didn't do the necessary leg work. There are some curious choices of courses to review: Hankley Common included with only 3 Colt holes? Ditto for Royal Worlington, Formby, Ganton, Alwoodley.. all not really Colt courses. On the flip side, many excellent purely Colt courses have been inexplicably left out. There's also only one course in the USA: Pine Valley. None from Canada? Virtually nothing on Alison in Japan.
There are quite a lot of mistakes too in the stated facts, labeling of photos etc
On the plus side, many of the modern photos are great and the big find are the original Colt sketches of Edgbaston GC which are very nice."
I just get the impression from the book that they just want to make money from the publication and did not have any real interest in Colt or any passion for the subject.
I cannot find a reference list in the back of the book either.