THE THIN, FRAIL MAN sits where he spends most of his time these days, propped up in bed, as smoke from his cigarette rises in the darkened room and his voice, fragile as an eggshell, scratches against the silence, It is a familiar voice, profane, urgent, its cadences as recognizable as the profile of Richard Pryor's head that bobs forward briefly into light and drops back onto the pillows. A loaded Smith & Wesson .357 Magnum rests on the nightstand next to the bed. His fingers are barely strong enough to pull the trigger anymore, but Pryor, a longtime gun freak and part-time paranoid, likes to keep the pistol within reach. It's like this, he says, in his weak, often faltering voice: ''Since the earthquakes last year didn't kill me, the drugs didn't kill me, the fire didn't kill me (although it hurt like a bitch), and my ex-wives (God bless them all) didn't kill me, there is no way I'm going to let the MS kill me. But, yes, I think about dying. I just don't want to die alone, that's all. That's not too much to ask for, is it? It would be nice to have someone care about me, for who I am, not about my wallet.'' These are not the best of times for Pryor or his wallet. Yes, he has survived the years of cocaine, the near-fatal burns from a 1980 suicide attempt, and the fallout from six broken marriages. But the onset of multiple sclerosis in 1986, and quadruple bypass surgery in 1991, have left him debilitated, and-because he's too sick to make films-close to broke. Needing money, Pryor, 52, returned to the concert stage last October after a six-year absence, playing 3,000-seat halls at $55,000 a night. The effort, however, exhausted him. Now he's trying less demanding venues at $30,000 a night, and hoping to start April 27 in Anchorage. Although it's leased, Pryor's ranch-style, four-bedroom home in Beverly Hills still gives the impression of wealth. The living room is decorated with art by Miles Davis, an album cover signed by Charlie Parker, boxing gloves autographed by Evander Holyfield, and photos of Pryor with Quincy Jones, David Letterman, Al Pacino, and just about anyone else who ever made an impact on entertainment. It's an impressive gallery, sketching the history of a man whose lewd and perceptive riffs, delivered in concert, albums, and films (see filmography on page 22), revolutionized comedy. Double doors at the end of a long hallway lead to the massive master bedroom. There are more photos here-of Pryor with his friends and children, Rich Jr., 31, Elizabeth, 26, Rain, 23, Steven, 8, Franklin, 6, Kelsey, 5, and his 4-month-old grandson, Randis. (He doesn't acknowledge Renee, 35, as his daughter, though she has been photographed with him and referred to as his daughter in the past.) A 50-inch TV, part of his payment for his last movie, 1991's Another You, dominates one end of the room. Talking is difficult for Pryor. His voice is often reduced to a whisper and broken by fatigue. But he wants to talk. After years of virtual silence about his health, the time has come, he says, ''to tell the truth, to open the soul.'' In this interview, conducted slowly over a three-week period, Pryor talks about his sickness, the prospect of death, and his great, tenacious hope-with no loss of his characteristically wicked humor.