(CNN) -- You would think surgeon Marty Makary might have a lot of doctors and hospitals gunning for him.
His new book, "Unaccountable: What Hospitals Won't Tell You and How Transparency Can Revolutionize Health Care," is an eye-opening look at the culture of medicine. And it's not pretty.
-- Dangerous doctors, who keep practicing because of a code of silence among their colleagues.
-- "Fred Flintstone" doctors, who are woefully behind the times in their skills, but won't tell you.
-- Profit-hungry doctors and hospitals, who take "sales commissions" from drug and medical device companies for using a certain drug, or implanting a certain device in patients.
But for every doctor who has called him a traitor, Makary says, five have thanked him for telling the story behind the statistics, which show that one of every four patients who is hospitalized is harmed by a medical error.
Aside from errors, experts say 20% to 30% of medical care is unnecessary.
Makary is a surgeon at Johns Hopkins Hospital in Baltimore and a professor at Johns Hopkins School of Public Health.
He says he wrote the book because he wants to change the system from the inside out. He doesn't think the government can solve the broken health care system, and he doesn't think the marketplace can either.
"It's the patients who can change it," he says, by pushing to change the way doctors and hospitals do their jobs.
Patients can do that, he says, by becoming sharp consumers of health care -- the way they might be with any other product or service they buy.
Makary gives some tips on how to do that:
-- If you don't know who's a good doctor and who's not, ask hospital employees.
-- When a doctor proposes surgery, ask questions: What happens if I don't do this? What other options do I have? What are the risks and the benefits?
-- Get a second opinion.