Is there a definitive book on aging and life stages?

Answer 1

Try .....

The Stages of a Man's Life by E. James Wilder (Author) or,

Passages: Predictable Crises of Adult Life by Gail Sheehy

both are highly regarded.

Answer 2

(1) The Hindu texts have described several periods of
life time. Baalyam means childhood period upto 10 years
of age. The period between 12 years and 25 years is
called Koumaaram which roughly corresponds with
adolescence. Within this period, Kurra means the age of
16. This is called the age of eternity. Russian
scientists have found that if the control systems in
the body are maintained at the same level of efficiency
as they are at the age of 16 years, using some
machinery or electronic control system, a person can
live for 10000 years. The Puranas say that people in
Krita Yuga (the golden age according to esoteric texts)
lived for 10000 years. However contrary it may be, this
very age of eternity is also the age of commencement of
the period of gradual death. Some Hindu texts say that
there is divinity in children. The possible
interpretation of this line could be that this process
of gradual death does not touch children until they
reach the age of 16 years. (Most children who die
before the age of 16 are due to external factors,
malnutrition etc). This is verified by the fact that
the percentage of persons who die at the age of 16 are
the lowest compared to any other age. This fact
observed by ancestors went into fairy tales which say
that a princess will die on her 16th birthday. Modern
medicine has found that 'brain sand' starts forming in
the pineal gland after the age of 16. The pineal gland
is the third eye, and it is the seat of Mukya Prana
(chief life) according to ancient Yoga and Tantra
texts. Modern madicine found that a person can lead an
almost normal life evern if 30 to 40 percent of brain
matter is removed. But no person survives if the pineal
gland is removed.

(2) The pulse rate in a new born baby is about 140
beats per minute. This pulse rate gradually reduces
during the Koumaaram period and settles down to it's
stable value of 76 beats per minute after the age of 24
years. Different sects in the world have different
criteria to declare a person to become a youth. The
Indian tradition says that a person becomes a youth on
his 25th birth day, taking the stable heat beat value
into consideration.

(3) Modern psychologists treat the period from 35 to 40
years as middle-age crisis period. Most of the people
may not feel much during this period. However for those
few persons who experience its full intensity, it will
be like a mini-death. In English, 'flourit' means the
age of dawning of wisdom; it also means the age of 40.
(See a multi-volume dictionary in a library). Energy in
the body will be at its highest during the youth period
from 25 to 40 years of age. Generally, Buddhi
(intellect) starts funtcioning after the age of 40
years, but it may take longer for others. You can not
blame a teenager or a youth for not having it. It is a
general observation that only person aged beyond 40
years are called intellectuals.

(4) The period from 40 to 60 years is called the
declining period of youth-hood. It is also the period
of gaining wisdom.

(6)The age beyond 60 years is called old age.

Answer 3

Erik Erikson made significant contributions to the
discussion on aging and life stages.

http://en.wikipedia.org/wiki/Erik_Erikson