Best general guide to Scottish genealogy? to English genealogy?

If I had to name just one reference guide to Irish genealogy, I would not hesitate to say John Grenham’s Tracing Your Irish Ancestors. As a general, all-purpose guide, there’s no question that this is the book: it is very well-written and very well-organized; both comprehensive and comprehensible; and also just smart and insightful, which makes it a pleasure to use.

Is there a comparable ‘the best general guide’ to Scottish genealogy? to English genealogy? and I suppose I should also add, to Welsh genealogy? (and why is Wales so frequently overlooked?)