Having survived until the age of 21, a male member of the English aristocracy in this period could expect to live: 1200–1300: to age 64 1300–1400: to age 45 (due to the impact of the bubonic plague) 1400–1500: to age 69 1500–1550: to age 71
Now the above is noble men. But look at that date. 1550. People were living to 71 in 1550. That is only about 10 years below what we have in the USA.
The best book on programming for the layman is "Alice in Wonderland"; but that's because it's the best book on anything for the layman.