Last Days of Ptolemny Grey, by Walter Mosley is told from the perspective of an old black man suffering Alzheimer's, fading in and out of memory and consciousness.
Ptolemny is given drugs to help him recover memory, with the foreknowledge the gift will likely shorten his life. Still, he makes his deal with the Devil. The altered consciousness doesn't change who Ptolemny is at his core, but his improved mental capabilities help him execute his sense of justice.
Characters from Ptolemny's past become visions and in lucid sdreams he rewrites history. Waking life becomes dreamlike, an odyssey where he uncovers fragments as though a detective in his own life. It is a treasure hunt that will benefit future generations.
It is also a love story, told with a yearning that he was forty years younger and Robyn twenty years older.
Samuel Jackson is working to help bring the book to screen through HBO, but there's nothing on imdb just yet.