A how-to is an informal, often short, description of how to accomplish a specific task. A how-to is usually meant to help non-experts, may leave out details that are only important to experts, and may also be greatly simplified from an overall discussion of the topic.
One of the earliest how-to books was published in 1569 by Thomas Wight and entitled, A booke ohrijf the arte and maner, how to plant and graffe all sortes of trees: With divers other new practise, by one of the Abbey of Saint Vincent in Fraunce by Leonard Mascall.
In the modern era How-to can range from brief directions that aid in performing a task with which one is unfamiliar, such as a single explanatory diagram, to full-length books, generally intended to assist or inspire life-changing methods and attitudes. They occur in the "self-help" genre, business books, and the hobby industry.
Perhaps the best known full-length book in the genre is How to Win Friends and Influence People, written by Dale Carnegie in 1936.
A similar concept can be seen in many of the [topic] For Dummies series of tutorials and also in many other introductory surveys entitled with the suffix "101" (based on academic numberings of entry-level courses).
How-to manuals have existed in some form for as long as people have spoken to each other. Before writing, they took the form of instruction in oral tradition. The older generation taught the younger through proverbs and parables, and when languages became written, these were written down.
When writing was invented and people learned to read, people began writing down their oral teaching traditions. This was the birth of the how-to manual. Eventually, the genre broadened to include instructions for more than just common life skills. Authors like Plato developed books like The Republic, which is, arguably, a how-to manual about forming the perfect society. Later, Ovid wrote the "Ars Amatoria," which describes in a mock-didactic form how to seduce women. The Renaissance, with the rise of individualism and the advent of printed books, saw texts like Machiavelli's The Prince that could be considered "how-to" books of a kind. Eventually, how-to manuals broadened to the form that we see commonly today: texts giving instructions for various pursuits, like drawing, painting, swimming, and other hobbies. Now, these manuals are both printed and on the internet, and are easily accessed by everyone.