Refers to something or someone that provides direction, information, or leads the way. Often used in literary or formal contexts.
この本は旅行のしるべとなる。
This book serves as a guide for the trip.
彼は私の人生のしるべだった。
He was the guide of my life.
That teacher became a guide for many students.
This book will probably serve as a guide toward success.
When lost, people naturally seek guidance.