My mother's family are Morgans, and I have them on both sides of the Atlantic. I have no practical experience of the books that you speak of, but I have never come across one in the UK.
You realise, of course, the Morgan is a Welsh family name, which like most Welsh family names became surnames at quite a late date in history. The Welsh preferred the patronymic system.
Morgan is, perhaps, especially important in the county of Glamorgan, or Sir Morgannwg (the i in Sir should have an accent like the French circumflex, but my keyboard cannot cope with it! The word is pronounced in a similar way to the English Shire, and Morgannwg sounds like Morganwy).
My own Morgans were from the county of Monmouthshire, at least as far back as I have been able to trace thus far. Glamorgan is the next traditional county to the west. However, like many Welsh family names they are now well dispersed throughout most parts of the UK, and there are a fair few in Argentina! Then, of course, the US, the great melting pot of international peoples.
Your problem is that the Morgans in the UK (and by extension, throughout the world), are not necessarily related in any meaningful manner. So a family book on what is one of the most common Welsh surnames is unlikely to be comprehensive - even if it made War and Peace look like a slim volume!
Good luck with your searches.