Human, All Too Human: A Book for Free Spirits (Menschliches, Allzumenschliches: Ein Buch für freie Geister) is a book by 19th-century philosopher Friedrich Nietzsche, originally published in 1878. A second part, Assorted Opinions and Maxims (Vermischte Meinungen und Sprüche), was published in 1879, and a third part, The Wanderer and his Shadow (Der Wanderer und sein Schatten), followed in 1880.
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. Reflecting an admiration of Voltaire as a free thinker, but also a break in his friendship with composer Richard Wagner two years earlier, Nietzsche dedicated the original 1878 edition of Human, All Too Human "to the memory of Voltaire on the celebration of the anniversary of his death, May 30, 1778". Instead of a preface, the first part originally included a quotation from Descartes's Discourse on the Method. 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) compelled him to request a leave of absence from his academic duties at the University of Basel. In the autumn of 1876, he joined his friend Paul Rée in Sorrento, at the home of a wealthy patron of the arts, Malwida von Meysenbug, and began work on Human, All Too Human.
The genre of the aphorism was already well established at the time of writing this book: in the German tradition, Nietzsche's most important predecessor was a figure of the Enlightenment, Georg Christoph Lichtenberg, whose writing Nietzsche greatly admired. Nietzsche's work is indebted also to Schopenhauer's, particularly his Aphorisms for Practical Wisdom (1851). Above all else is the "debt to the French tradition of the aphorism – for Nietzsche's work is a deliberate turn westward".