I feel as if I have been reading this book forever, but I excuse myself as it is a massive chunk of a book and hardly a light read. I have owned it for years, and dipped into it when I was doing my undergraduate philosophy degree. Not long ago I was reading some Popper, and he made a number of complimentary remarks about certain presocratic philosophers that encouraged me to go back and read this.
Now, I am pretty confident this book is going to be of minority interest. Philosophy books generally are, but ones about philosophers from thousands of years ago? I doubt that many readers will be taking it up. I have a reasonable grounding in philosophy, but this is the only book I've ever read on the presocratics (that is Greek philosophers who came before Socrates so we are talking 400 BCE or earlier). I also have no capabilities in Greek, let alone ancient Greek. Given this I have no comparison for how good or reliable Barnes's views are. So take this as the views of someone on reading this book and purely this book. If you are an expert in presocratic philosophy you may well disagree.
The presocratics vary from reasonably well known names such as Heraclitus (famous for "you can't step into the same river twice), or Democritus and Leucippus (the atomists) through to some fairly obscure thinkers.
I need to say what Barnes doesn't do first. Barnes does not set out to give a full linguistic exposition of presocratic thought. And given we are talking about small fragments of ancient Greek, this is often the focus for academics. He does though say enough to show quite how hard translation and interpretation based on those few fragments is. Much emphasis on this work over the years has simply been trying to translated and string together various fragments to work out what they said without analysing it. I am in awe of people who have done this! He does not set out either to give historical or a history of ideas context to their works - but again he says enough to give some appreciation of this.
What he does is try to extract the arguments that the philosophers made. We mostly think of them as people who came out with what sound like really bizarre statements - such as everything is water, change is not possible, or oddly modern sounding claims like everything is made up of unchangeable atoms bumping around into each other. But if you take these statements as stand alone statements you will never appreciate the presocratics. For they did not just make these claims, they built arguments for them. Some of these arguments are good, some bad - but they are arguments which differentiates them from many ancient thinkers who just seem to make claims without rational argument to back them. It is these arguments that Barnes identifies from the often peculiar, poetic, and down right difficult to interpret language. In the history of ideas the step from simply making claims to developing rational arguments for those claims is incredibly important.
I suspect few people sit down to read this end to end. I have, but over several weeks dipping in and out whilst reading a myriad of other things. I really enjoyed it, enlivened by Barnes's often mischievous and very English wit which he litters his writing with.