Lucretius - The Nature of Things (Penguin Classics, 2015) ****

Sometime in at the beginning of the first Century BC, Roman poet and philosopher Lucretius wrote his "Rerum Naturae", a lengthy poem on the nature of things, as its title suggests. It hails back to the teachings of Greek philosopher Democritos (c. 460 – c. 370 BC) who claimed that reality existed of atoms, tiny particles that interact with each other and together create the different forms of matter, life and even mind. Lucretius adds the thoughts of Epicurus, another Greek philosopher (341–270 BC) who "asserted that philosophy's purpose is to attain as well as to help others attain tranquil lives, characterized by freedom from fear and the absence of pain" (Wikipedia). In this context, deities are no longer necessary to explain reality, and hence there is no need for humans to live in fear and terror for the gods. 

The entire book was originally written as a poem, despite its abstract content. The English translation follows this approach, with rhymes and all, a true feat of the translator, for a book of close to 400 pages. The reading is still relatively easy, with the biggest hurdle of its lack of structure, build-up and endless repetitions.  In any case it's not a book that you read in one go. 

The poem disappeared from sight until one copy was found in 1417 by Italian scholar Poggio Bracciolini, who probably found the poem in the Benedictine library at Fulda, Germany. I can recommend "The Swerve" by Stephen Greenblatt for readers who would like to know more about the impact of Poggio's discovery on philosophy, and also in the broader context of enlightenment and humanism in Sarah Bakewell's "Humanly Possible". 

By any measure, even after thousands of years, Lucretius still reads like a modern-day person. It is astonishing how many obscure ideas have flourished in the intervening time, and even more so that most people are still living in "this dread, these shadows of the mind": 

"This dread, these shadows of the mind, must thus be swept away 

Not by rays of the sun nor by the brilliant beams of day, 

But by observing Nature and her laws. And this will lay 

The warp out for us — her first principle: that nothing's brought

Forth by any supernatural power out of naught.

For certainly all men are in the clutches of a dread - 

Beholding many things take place in heaven overhead 

Or here on earth whose causes they can't fathom, they assign

The explanation for these happenings to powers divine.

Nothing can be made from nothing - once we see that's so, 

Already we are on the way to what we want to know:

What can things be fashioned from? And how is it, without 

The machinations of the gods, all things can come about?" (p.10-11)

And one of many passages on the atoms themselves: 

"Then furthermore, since when we peer at objects, there must be
An ultimate, smallest point which is the smallest we can see,
So also in things, there is a smallest point beneath our sight, 

And this contains no parts, being of a stuff so slight, 

It is the smallest stuff of all. And it can never start 

To exist as something separate, because it's always part 

Of something else, primal and indivisible. The way 

Matter is composed is from such parts in tight array.

And since they can't exist alone, then they must closely cling

To the atom, and cannot be torn away by anything.

Atoms therefore are a pure and simple solidness,

Made of those smallest parts cohering tightly in a mass.

Atoms aren't assemblages made out of parts; they get 

Their might from their eternal singleness. Nature won't let 

Anything be wrenched from them, or any dwindlings, 

But keeps them in one piece preserved to be the seeds of things." (p.38)

And of course, when thinking things through, there is no immortal soul since our mind is the result of the physical activity of our body and our senses. 

"As it creeps across the other members. And thus because the spirit
Is divided up and does not, when it leaves the body, clear it 

All in one piece, then it is mortal too. If you should think 

The spirit has the ability to retract itself and shrink 

Into a single spot and pull its particles together 

And so withdraw sensation from one limb after another, 

Consider that the place in which the spirit then condenses 

Should have, by rights, a corresponding heightening of the senses;

But seeing that there's no such place, again I must declare, 

It perishes, being torn to shreds and scattered to the air.

And even if, just for the sake of argument, I grant 

That spirit can be concentrated (though in truth it can't) 

In the flesh of those who leave the Light by dying bit by bit - 

The spirit's mortality is something you must still admit.

For whether the spirit perishes abroad, for winds to scatter,

Or shrinks up in a ball and goes inert, it does not matter - 

Either way, sensation fails the man on every side, 

And everywhere there's less and less life in him to abide." (p. 139)

So mind requires the body - the actual man - in the same way
In order to exist, because the flesh contains the mind - 

The body being, as it were, a vessel of a kind - 

Or maybe there's some other metaphor that makes it plainer,

Since mind and flesh are closer bound than contents and container. (p. 140)

 Highly recommended.