Literally speaking, Yoga Sutra would mean a narrative on Yoga science. Yoga was actively practiced by ancient Indians since 3000 BC however it was compiled into a literature much later. This literature guides the reader with correct details on Yoga that can be followed with out any confusions or complications. The credit of putting Yoga into text goes to sages of Pathanjali clan. The exact date of the origin of Yoga Sutra is debatable and could be anywhere around 200 BC.
The obvious idea behind creating Yoga Sutra was to teach the right method of doing Yoga Aasans. For the benefit of people, Pathanjalis compiled this book. In that era, ideally there was no need for such literature as the Sages then were well versed with authentic Yoga. Yoga Sutra came into existence probably as a result of the foresight of the sages. They foresaw the need for a guide to proper Yoga techniques for the coming generations use.Yoga Sutra is divided into four main sections namely the Samadhi Pada, Sadhana Pada, Vibhuti Pada, Kaivalya Pada. Each section aims not only in taking the individual closer to a healthier lifestyle but closer to Self realization also. It explains how to control the mind and be physically fit through different types of Yoga Asanas. There are 195 plus one (added later) Sutras (thoughts) covered in these four sections. Originally, written in Sanskrit Yoga Sutra it has been translated into English also.
This has proved to be an ideal guidebook, for all those interested in learning authentic Yoga.