Miriam Bass, the well-respected book marketing expert widely known for the "News Breaking Now" newsletter she wrote for the National Book Network, died September 6 of heart failure. She was 52. Bass began her career in the book business in 1971, while still a student at UCLA, working as assistant to the general manager and director of advertising at Hunter's Books. For 14 years, starting in 1980, she was assistant v-p for merchandising at Crown Books. She became director of marketing for NBN in 1994 and rose to the position of v-p for marketing and new business development. Bass continued to work despite a number of health issues, including a kidney transplant. Family members suggest that in lieu of flowers donations be made in her memory to the National Kidney Foundation at 30 E. 33rd St., Suite 1100, New York, N.Y. 10016. A memorial service was held last Friday in Los Angeles.