IGN flagged the discount on October 19: The Legend of Zelda Encyclopedia is currently listed below its standard price at Amazon. No bundle, no collector's edition, no pre-order trinket — just the book, cheaper than usual.
It's the third of Dark Horse's Zelda hardcovers, following Hyrule Historia and Art & Artifacts, and it's the one built for people who want the receipts. Character histories, dungeon breakdowns, item catalogues, and an annotated timeline of a series that has spent four decades cheerfully contradicting itself. Reading it cover to cover is a chore. Keeping it within arm's reach while you argue about which Link did what is the actual use case.
One caveat, stated plainly: Amazon pricing on hardcovers like this drifts daily. IGN's post didn't spell out the discount percentage, and collector-facing books tend to clear fast once word gets around — after which the listing snaps back to full price. Check the number on the page before you hit buy, and if it's still low, don't sit on it for a week.
There's a second argument for grabbing it now. Zelda hardcovers have a long history of going out of print and then fetching silly money on the secondary market, which is a roundabout way of saying the cheapest copy you'll ever own is usually the one you buy at a discount while it's still in stock.
It's a book, not a game. But it's the most complete single-volume archive of the series' lore you can put on a shelf, and the price today is better than the price next month.