I am often asked which book I would recommend among the translations of The Yoga Sutras of Patanjali. I have collected many different books over the years and here are three of my favorites translations ( not in any order ).
1) ALISTAIR SHEARER -This book reads easily, is organized with the commentary first and the sutras compiled after. The size of the book is easy to travel with, and the language used is easily understood and contemplative for these modern days.
2) BKS Iyengar- This book requires your intelligence, patience, and has a depth of information for a lifetime. Sometimes the commentary is difficult to understand as it is so comprehensive and referring to many yogic terms and concepts. The direct translation is given based on the sanskrit with the various words that could be used for the translation of the sanskrit word are give with each sutra so you have a better understanding of the nuance of the sutra. There is also lots of extra information and graphs about yoga that are useful if not at first, over time as your yoga study deepens. As your knowledge and experience of yoga grows over time, so will your understanding and appreciation of this book.
3) EDWIN F BRYANT-this book is practical for study and filled with commentary based on references from different sources and authorities. Different yogic schools of thought are also presented when applicable, as is the Buddhist perspective when opinions on topics diverge with yogic ones. Detailed explanation with additional back ground information on various yoga related subjects make this a great addition to a collection.
The Yoga Sutras of Patanjali are meant to be studied with a teacher, reflected upon and referred to throughout life for inspiration, guidance and general study. In my view these books are as necessary as a mat for the practice of yoga and even more so for ones development in yoga.