practical guide; manual; how-to book
A book that teaches practical skills or knowledge, such as cooking, gardening, or software usage.
I bought a practical cooking guide and try recipes every day.
This how-to book explains how to use a computer in detail.
マニュアル is a manual, often for a specific product or procedure, and can be more technical than a general 実用書.
Compound of 実用 (practical use) + 書 (book). The word follows a standard Sino-Japanese pattern for types of books.