handbook
A small book that gives important rules or instructions.
A handbook is a small book or manual that explains how to do something or provides important information about a specific topic. Think of it as a guidebook you can carry with you, designed to answer questions and help you understand the rules, procedures, or basics of whatever it covers.
Schools often give students a student handbook at the beginning of the year, packed with information about dress codes, attendance policies, and what to do if you need help. A handbook for a new board game explains the rules so players know how to start. An employee handbook tells workers what their company expects and what benefits they receive.
Unlike a thick textbook that explores a subject deeply, a handbook focuses on practical information: what you need to know to get started or handle common situations.
Museums and national parks often provide visitors with handbooks describing what they'll see. Scout troops use handbooks to teach camping skills and requirements for earning badges. When you're learning something new or joining an organization, a good handbook becomes a trusted companion, ready to answer your questions whenever you flip it open.