I was drawn to this book one fine day, listening to an interview given by the author – a Nobel Laureate – with Neil deGrasse Tyson in the SpaceTalk show.

A fascinating thing about death that I have observed is that while this is the one given thing – perhaps the only given thing – moment we are born, we are, as individuals and as a group, a bit unwilling to talk about it. Trying to bring the topic up with my own family, even in the context of planning out what happens after my death, I immediately face angry demands of why I would bring up that topic. A Martian would have observed these discussions and concluded that we do not talk about death, perhaps because not talking about it will make it go away.

In the interview, Venki starts by asking, “What is death?” This seemingly innocuous question has some interesting facets. We have none of the cells we were born with. Are we dead? We have cases of reviving people whose hearts had stopped. Were they dead? In fact, Venki goes on to expound on the deaths of cells and tissues, simple animals, human beings, and then takes on the deaths of towns, villages, countries, and civilizations.

This book digs into the physiological causes of death. Quite paradoxically, after spending centuries and billions of dollars, while we understand a lot about what happens to our bodies at the sub-cellular level – and that has given rise to great medicines – we are still not entirely on the up and up about what really causes aging.

That said, we have come to understand that the same mechanism that prevents cancer also gives rise to aging. Evolution has made sure that the cancer-preventing mechanism dominates in our youth when we can reproduce, even if it comes at the cost of aging and dying when we cannot.

The author is fairly down on attempts by humans (he is particularly tough on the rich – especially the Silicon Valley moguls) who are trying to live forever. Even if it were possible – and he expressly believes this cannot be true – he points out the troubles it will cause to society, the economy, and one’s own quality of life. Living forever is not the same as setting the clock back. You are not going to be in your 20s again. In fact, he points out that we have doubled our life expectancy in the last century. We are not exactly that happy with the extra time we have!

But, what blew me away was the origin of the mitochondria, which is central to aging.

One of the finest philosophical comments when paraphrasing another author is “Life is an interruption in an eternity of personal nonexistence.”

Some of the other interesting thoughts that caught my attention.

* It is a curious facet of human psychology that even if we accept that we ourselves will be gone, we feel a strong need to be remembered.

* Unlike humans, most insects and grain crops reproduce only once.

* Natural selection rarely asks for the good of the species or even groups. It is entirely focused on an individual’s fitness – defined by the ability to reproduce.

* Menopause is a curious phenomenon unique to humans, mostly. Why such an abrupt change in a female from being able to reproduce to not being able to is not fully understood.

* Mammals typically have roughly the same number of heartbeats over their lifetime – about 1.5 billion. Humans did too. Till we figured out in the last century how to double our lifespan with the aid of hygiene and medical science. Humans were the same, except that in the last 100 years, our lifespan has doubled.

* DNA’s damage response is a balance between cancer and aging. It is a mechanism that has evolved to benefit early in our life – when we are likely to pass our genes, even if it costs us later.

* Larger species generally live longer than smaller ones because they have slower metabolisms and can also escape predation. But within species, smaller breeds generally live longer than larger ones. This might have something to do with how much growth hormone they make.

* There is strong evidence that damage to our mitochondrial DNA is an important factor in aging. Mitochondria themselves are the evolutionary descendants of a bacterium that was swallowed by a single-celled organism. Over millions of years, the bacteria managed to transfer most of their genes into the host’s genome while retaining a few. The reason is not quite well understood.

* We inherit these mitochondria entirely from the mother’s side.

* Physical activity turns on some of the same pathways that stimulate mitochondrial production in tissues ranging from our muscles to our brains.

* Although the number of centenarians has grown in recent decades, the number of supercentenarians (110 years or older) has not changed and remains very small.