The fact that this book is for 5th edition makes it wonderfully useful, even for backwards compatibility, but in 5th, it fits a wonderful niche overlooked by anything officially released, namely, informationon Warlock Patrons.
Immortal Domains combined with Warlock Patronage equals a campaign, from both a PC Warlock--, as well as the Patron Immortal's perspective; a campaign in which the setting can be forever altered in favour of the Patron Immortal and its loyal Warlocks, whether taking place over the span of centuries, or in a swift revolution. All of this is augmented by the time powers and the ability to edit events on the fly...
Top notch ideas, great implementation, and forgivble use of some sort of pink chart and box text highlihgting.
I've purcha$ed a printed copy, and, I suspect that you will, too.
[5 of 5 Stars!]