I remember once, thinking what it would be like living in the body of a young woman I'd seen walking with ease down the other side of the street.

This was a day when my own aches and pains were in sharp focus.

For a moment, I fantasized that her life was a better one.

Then the thought came: she was probably living with chronic endometriosis and this was one of her good days.

This was not a vindictive, nasty thought, merely a recognition that no life is without its challenges.

No one gets to live a full life without knowing what it is to be vulnerable - even those who look good on the outside.

This book tells some of my story: a story of living with a disease that will most likely take my life.

Over the years the horizon has continually shifted.

At times it is hardly discernable and at others there is a clarity that is quietly confronting.

Living well is the challenge and actively choosing what is at the centre of my life, the critical element.