[3] The book is Nietzsche's first in the aphoristic style that would come to dominate his writings, discussing a variety of concepts in short paragraphs or sayings.

Nietzsche later republished all three parts as a two-volume edition in 1886, adding a preface to each volume, and removing the Descartes quotation as well as the dedication to Voltaire.

In 1876, Nietzsche broke with Wagner, and in the same year his increasingly bad health (possibly the early effects of a brain tumor)[4][5] compelled him to request a leave of absence from his academic duties at the University of Basel.

[7]: xv  Nietzsche cites the French aphorists Jean de La Bruyère and Prosper Mérimée, and in Aphorism 221 celebrates Voltaire.

"[7]: xix  The aphorism "allows for a loosely organised, shifting whole containing specific ideas but no iron-clad explanation for everything, – [it] constitutes the style that best represents his philosophy".

[7]: xiv This book represents the beginning of Nietzsche's 'middle period', with a break from German Romanticism and from Wagner and with a definite positivist slant.

This section, named in honor of his friend Paul Rée's On the Origin of Moral Sensations, Nietzsche challenges the Christian idea of good and evil,[8] as it was philosophized by Arthur Schopenhauer.

When we see a waterfall, we think we see freedom of will and choice in the innumerable turnings, windings, breakings of the waves; but everything is necessary; each movement can be calculated mathematically.

[10] This can be interpreted as a veiled attack on his former friend Wagner (a strong believer in genius), though Nietzsche never mentions him by name, instead simply using the term 'the artist'.

[11] Here, Nietzsche criticizes Charles Darwin, as he frequently does, for being naive and derivative of Thomas Hobbes and early English economists, as well as for being without an account of life from the 'inside'.

[12]Nietzsche writes of the 'free spirit' or 'free thinker' (German: freigeist), and his role in society;[13] a sort of proto-Übermensch, forming the basis of a concept he extensively explores in his later work, Thus Spoke Zarathustra.

These two sections are made up of very short aphorisms on men's, women's and the child's nature or their 'evolution' in Nietzsche's subtle, anti-Darwinian sense.

Like sections six and seven, Nietzsche's aphorisms here are mostly short, but also poetic and at times could be interpreted as semi-autobiographical, in anticipation of the next volumes: "He who has come only in part to a freedom of reason cannot feel on earth otherwise than as a wanderer".

Faber was critical of Zimmern's "antiquated Victorian style" which, in her opinion, makes Nietzsche read "like a fusty contemporary of Matthew Arnold".