Atkins has written a book full of meaning. It is not simply an exposition
of the Second Law of Thermodynamics (that entropy can never decrease)
but an analysis of its consequences, which are vastly more profound
than one could think. Not only would the universe be completely different
without that asymmetry in entropy's evolution, but life itself would not
exist. Atkins begins by presenting the historical facts and introducing
the main characters. But then he follows his own logic, a modern logic
that deals with chaos and structure rather than steam engines.
The story really begins in the 1850s when "energy" displaced "force" as the key concept in Physics. Physics became the science of energy.
Atkins shows how the second law of thermodynamics was successively reinterpreted: there can be no natural process whose only effect is to turn heat into work; there can be no natural process whose only effect is a transfer of energy from a cooler to a hotter system; natural processes inevitably cause an increase in the entropy of the universe. These statements are all equivalent but it took great minds to understand it.
The key was to understand that heat is not a substance or a form of energy, but a method for transferring energy. Ditto for work. However, heat and work are not equivalent: work can be converted into heat, but the viceversa is not quite possible. Heat cannot completely be converted into work. As Atkins puts it, "heat is taxed, work is not". It is just a property of our universe.
It turns out that this "tax" is related to entropy, and entropy is a measure of chaos. The conversion of heat into work is the history of human civilization. We mined the Earth to find the heat left there by primordial processes, for example under the guise of fossile fuels, and, in the future, of hydrogen (the oldest fossil fuel of all, left around by the Big Bang itself) When humans started burning fires, they merely started using the energy gifted to the Earth by the Sun. The conversion of heat into work required another step: engines. The history of the industrial revolution is the history of producing work at will.
Atkins shows that creating chaos may lead to coherent motion. Operations of chaos become the drivers of change. The constructive power of chaos suddenly becomes the real protagonist of the book. And out of this power there emerges life itself: the flow of energy-mass through a system causes dissipative structures from which complexity spontaneously emerges (i.e., reduction of entropy) while increasing the entropy/chaos of the universe. These complex structures dwell in a state of non-equilibrium until... they die. Energy disperses, but it does so slowly. And in the process of creating chaos it also creates structures.
Indirectly, Atkins paints the bleak picture of a purposeless universe that is simply bound towards chaos and, by sheer accident, also creates ordered structures such as me.