This is a text book. It’s an excellent accompaniment to a class on the Yoga Sūtra. In it all the sūtra-s are presented in both the original Sanskrit and in the transliterated roman language equivalent. It also has a word by word translation and a short discussion of each.
It is the best translation of the Yoga Sūtra that I know of. It was written by a long-term student of Mr. TKV Deśikachar – who is the source of my translations of the Yoga Sūtra. However, I will warn any student – it is almost impossible to get anything meaningful out of reading the Yoga Sūtra on your own. You really need to take a class with a qualified teacher to have it all make sense.
Reading the Yoga Sūtra is like reading a text on music theory. Without actual practice of music under the guidance of a qualified teacher, it won’t be very interesting reading.