Long Life Equation
For each of the factors listed Macnair gives the number of years that it can add or subtract to your life. It's surprising what can affect the length of your life - being married can add 7 years, and even a few stretching exercises each day can add an extra year. Bad posture can subtract two years so - sit up straight.
Of course it is best not to take these numbers too seriously. I worked out that if you did everything right then you could live to be over 250 years old - if anyone does ever live that long then I doubt whether it will have much to do with this book. But it does give a useful indication of the relative importance of the different factors which contribute to your health. You can compare, for instance the dangers of extreme sports with the problems of not getting enough sleep. It's also the sort of book that you can dip into from time to time, and hopefully pick up some useful advice.