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"Your biological age is the number of days you've lived.

Your psychological age is the number of thoughts you've entertained.

Your sociological age is the number of contributions you've made."

I am now 55 years old. Like a lot of people in middle age my late-night thoughts bend to contemplations about how short my remaining time is. Even with increasing longevity there is not enough time to do all that I want. Nowhere close. My friend Stewart Brand, who is now 69, has been arranging his life in blocks of 5 years. Five years is what he sa... See more

Six years ago I celebrated my 68th birthday by gifting my children 68 bits of advice I wished I had gotten when I was their age. Every birthday after that I added more bits of advice for them until I had a whole book of bits. That book was published a year ago as Excellent Advice for Living , which many people tell me they read very slowly, just on... See more