A set of two books, which are the most comprehensive look into Holdsworth’s approach to improvisation. It’s not just a transcription book (of which it has many), but instead a complete breakdown of what Allan is doing. I have them and it’s … heavy.
Here is a promo vid for it:
This is an interview with the Author:
You can get the print version of the books on Amazon, here’s the link to Brett’s site, which only has the ebook: