In his newest book, “Rethinking Aging: Growing Old and Living Well in an Overtreated Society,” the 69-year-old Hadler turns his attention to older Americans and the challenging medical decisions they face.

You’ve called your book “Rethinking Aging.” What do you want readers to understand about aging?

This book is a celebration of the fact that the baby boomers and the traditionalists — the generation that came before the boomers — are the first in the history of the world to hit age 60 and to be able to say, rationally, “What do I want to do with the next 25 years of my life?”

We shouldn’t worry so much about what will kill us; instead, we should be focusing on making it to age 85 and having a pleasing journey along the way.

You’re concerned about the medicalization of aging. Explain why.

You can be healthy well beyond 60, but you’ll be different than you were when you were 20. You’ll have different posture, wrinkles and a lot of other changes that are less obvious but age appropriate. We have to be very, very careful about calling any difference from when we were younger an illness or a disease. And we have to be even more careful about telling people that we have things we can do to “fix” these differences, but this happens all the time. That’s the medicalization of aging.

What’s the alternative?

Helping people understand what’s normal for their age and how to accept and adjust to those normal changes.

You talk a lot about the importance of older people making informed medical decisions.

For the first time in the history of medicine, we have a tremendous amount of information about efficacy: what makes sense to do medically and what doesn’t.

What I want to teach people is that it’s perfectly appropriate for patients to ask their doctors, “How certain are you that what you are offering me will produce meaningful benefits? What does the evidence show about the possibility of harm?”

Can you suggest some other questions people might ask?

People should want to know the likelihood that death will be postponed by doing something. What is the likelihood of the same outcome, or close to the same, if one doesn’t have the treatment? Out of every 100 people, how many are helped by this intervention?

What about people who face really serious, life threatening illnesses?