Conduct books or conduct literature is a genre of books that attempt to educate the reader on social norms and ideals. As a genre, they began in either the High Middle Ages or the Late Middle Ages, although antecedents such as The Maxims of Ptahhotep (c. 2350 BCE) are among the earliest surviving works. Conduct books remained popular through the 18th century, although they gradually declined with the advent of the novel.

In the introduction to her bibliography of American conduct books published before 1900, Sarah E. Newton defines the conduct book as

a text that is intended for an inexperienced young adult or other youthful reader, that defines an ethical, Christian-based code of behavior, and that normally includes gender role definitions. Thus "conduct book" embraces those texts whose primary aim is to describe and define a basically Protestant scheme of life, morals, and behavior, in order to encourage ideal conduct in white, generally middle-class children, young men, or young women.

Conduct books do not deal exclusively with questions of etiquette, but rather with the conduct of one's life in a broader, ethical sense. Conduct books are typically addressed to a specific audience but also to society more broadly, and address themes including moral education and gender roles. Their tone may be both admonitory and hortatory, instructing readers both on how to behave and how not to behave.

The critic Nancy Armstrong argues that conduct books "represented a specific configuration of sexual features as those of the only appropriate woman for men at all levels of society to want as a wife", while also providing "people from diverse social groups with a basis for imagining economic interests in common." Armstrong argues that conduct books addressed readers who belonged neither to the aristocracy nor to the working class, thereby paradoxically targeting a middle class audience that did not take shape until a later period—"a middle class that was not actually there."

In the Holy Roman Empire of the German Nation, Adolph Franz Friedrich Ludwig Freiherr Knigge wrote the book (1788) Über den Umgang mit Menschen (On Human Relations), a treatise on the fundamental principles of human relations that has the reputation of being the authoritative guide to behaviour, politeness, and etiquette in Europe. The work is more of a sociological and philosophical treatise on the basis of human relations than a how-to guide on etiquette, but the German word Knigge has come to mean 'good manners' or books on etiquette.

From the colonial period British and European conduct books were reprinted by American publishers and became popular; until the late 18th and early 19th centuries such imported volumes were the primary source of Americans' behavioral and moral guidance. American conduct books were addressed predominantly to middle-class readers and addressed middle-class concerns. Newton argues that these texts "reflected questions about gentility, right-doing, and manners, but more importantly questions about social identity and roles and how to live good and successful lives." A typical mid-19th-century conduct book for young women would deal with topics including women's responsibilities, domesticity and love of the home, religion, education, courtship and marriage, women's duties to their husbands and children, and "female qualities" such as cheerfulness, humility and submission; while a conduct book for young men of the same period would address themes including ambition, self-reliance, self-improvement, honesty, punctuality, choice of friends and marriage.

In her study of American conduct books published between 1830 and 1860, Jane E. Rose argues that conduct books in this period "glorify Republican Motherhood and domesticity" by characterising the home as the appropriate sphere for women, as a tool for "fostering religion, uprightness, and virtue", and as "women's empire" through which women serve the nation by raising future leaders. Topics covered by conduct books in this period "might include domestic, religious, and wifely duties; advice on health and fashion; rules for dating, mental improvement, and education; the art of conversation and avoiding 'evil-speaking' and gossiping; and advice on fostering harmonious marital relationships." Rose argues that these books, which were aimed predominantly at middle-class white women, placed "certain limitations and restrictions upon women's autonomy, literacy, and educational and vocational opportunities."