Bought a book for my birthday: "Cycling After 50". Think it is geared to a younger set.
At 77 I am not sure I want to expend the mental effort needed to pursue all the graphs, charts, intervals, heart monitoring, cupcake eschewing disciplines suggested. It makes me tired just to think of undertaking all that. Apart from an occasional slipped disc I am in pretty good health for my age. Cycling gives me great pleasure and freedom to explore my surrounding environment at a comfortable pace. In retrospect I am sorry I did not buy the book about the mechanics and history of the bicycle. Something about growing older has given me a great interest in how things work.