A bit dated by now, but I don't think much of this book has been disproven as of yet. I any case, one can only have respect for Davidson to have written such titanic book. The only downside is that he did not manage to do it clearly. The writing is definitely quite convoluted and he uses many archaic words (which is good for my vocabulary, but bad for readability. For instance I now know the words atavistic and staid).