Javier Marías’s magnificent, sui generis three-part novel, “Your Face Tomorrow” — all 1,200-plus pages of it — is consumed with the attempt to locate, parse and make music out of the deep grammar of language and power. While the prose is exquisite and never less than fluidly, balletically pleasurable, the project is both fundamentally troubling and fundamentally troubled. Every chamber of its heart is dark and uneasy, and though Marías brings matters to a close in the final volume, “Poison, Shadow and Farewell,” one might say that instead of coming to a definitive point, he has, instead, expanded the unanswerable questions to their farthest extent. The very last sentence merely pulls the pin on the final grenade. It’s as terrifying as it is beautiful.

“Your Face Tomorrow” requires patience, effort and intellectual discipline of the reader. “Poison, Shadow and Farewell” delivers a payoff at the end, but the real challenge, and pleasure, is in getting there.