Hi there,
I was playing a modpack with Integrated Dynamics and Akashic Tome mods, and noticed I can't put your book into the Akashic Tome...
The FTBWiki says:

By default, all items containing book, tome, lexicon, nomicon, manual, knowledge, pedia, compendium, guide, codex or journal in their registry names can be added to the tome (with exception of vanilla items like the Book).

Perhaps try this?

I won't be changing the registry name of the book, that would break all existing worlds.

I would suspect the mod has a config in which you can add additional books, perhaps you could try that.