hello. i am working over a book of humorous essays, and I'd like to quote some dead people on my back cover. but I am worried that people who own their estates would find cause to sue and I don't want to fight a lawsuit. How does that stand legally? plz help.

take the opinion of your publishers legal staff. as those that are clearly parodies or satirical would be protected, while those not, could be actionable.
make sure of not to hurt someone's feelings.