Largest and most comprehensive books on Celtic mythology?

This is the Routledge Handbook of Greek Mythology, 8th Edition:

https://www.amazon.co.uk/Routledge-Handbook-Greek-Mythology-ebook/dp/B07T3GC7LK

It's the largest and most comprehensive book I've ever acquired on Greek Mythology -- I'm basically looking for the Celtic equivalent of this, focusing on the mythology of Ireland, Scotland, Wales, etc.

As a side note: I tend to prefer books crammed with detailed information and rich wording over ones with pretty pictures, but I'm open-minded.

I'd appreciate any help. Thanks. ^^

Celtic Culture is most likely the most comprehensive one you'll find

Routledge has Celtic World covering all aspect of Celtic studies

>2 SandraArdnas: Wow - those are fantastic. Thanks for sharing! I'll have to look into them at some point.

If I could probe into your knowledge of mythological resources further:

1. Do you recommend any other books for people showing first-time interest in Celtic mythology? Still detailed and comprehensive, of course.
2. Do you happen to know of similarly good books on Roman, Egyptian, or Indian/Middle-Eastern mythology?

Thanks for your time. ^^

If it's not strictly mythology you're interested, but an overview of history and culture you might want to check that entire series Celtic World is part of. https://www.librarything.com/nseries/26517/Routledge-Worlds

Strictly mythology, there's https://www.librarything.com/nseries/32973/Handbooks-of-World-Mythology

>4 SandraArdnas: Thank you kindly for your help. ^^ Take care.

You're welcome. Perhaps I should also note that Oxford's Very Short Introduction series has a number of books on various mythologies. While they are introductory and probably not what you're after, they normally have good bibliography, so might be worth checking out at the library for that

>6 SandraArdnas: Wonderful. Thanks again! ^^