Book of Eclipse is a Quick-Play Spell Card.
Spell Cards are usually activated from the hand on your turn unless their type gives another timing window.
On the current TCG and OCG Forbidden & Limited lists tracked here, Book of Eclipse is Unlimited.
YGOPRODeck lists Book of Eclipse for these formats: Common Charity, Edison, TCG, OCG, Master Duel.
Book of Eclipse belongs to the Book of archetype—use that tag when searching for engine pieces and tech options.
A listed print of Book of Eclipse appears in 25th Anniversary Rarity Collection II (RA02-EN054) at Collector's Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Book of Eclipse is about $0.17 on Cardmarket (prices change frequently).
