This collection of essays addresses a broad range of subjects from Augustine to Kierkegaard and beyond, with examinations of existentialism which are enriched by her personal connections to both Jaspers and Heidegger. One of the most important group of essays addresses the titular subject of understanding itself. While addressing questions such as what is the proper basis for morality when faced with "the breakdown of its structure", she uses a thought process that I found not dissimilar to that of Ludwig Wittgenstein in his Philosophical Investigations.
She also considered the concept of "balance of power" both with regard to relations between nation states, but even more important she addresses the balance of power between branches of our constitutional government as based on the writings of Montesquieu among others. In addition she discusses the issue of fear in tyranny to which I would immediately draw comparisons with the thought of Machiavelli. This leads to raising questions like what is the nature of the "double standard "status of man as both citizen and individual".
One element that holds all of the essays together is the deep thinking of Arendt herself. This is evident in her method that continually goes back to the source of the issues and ideas under consideration referencing classical philosophy and religion where relevant. It is this deep thinking that makes this collection of essays essential for our consideration of how to understand the politics and ideological issues of the twenty-first century.