It's difficult to say what makes a great author. In my humble opinion, the best authors are those that combine both a great insight into what they are writing about and have the ability to express this through their writing (to be a good story teller).
In my extensive experience of reading, I have found that few authors combine both (a great mind with the ability to write well). When you do happen to come across an author who combines both it is a joy to read their books.
On this basis, here is my list of what I consider to be the greatest authors (and one playwright) of non-fiction of all time. Like with everybody, they can have their off days and some of their books occasionally don't make the grade (I would strongly recommend everybody to avoid James Joyce's 'Finnegan's Wake' like the plague).
To see what other people think about the authors in this list (don’t just take my word for it), click on the amazon image at the end of each of the authors listed. In addition, it'll also show you the book which I think is their best.
|10.||Mario Vargas Llosa||Now|
|15.||Bret Easton Ellis||Now|