Recently an American lady asked me to recommend an English translation of Bhagavad-gītā. Of course in America there are so many editions of Bhagavad-gītā available in English, but as far as I have seen, not only in America but also in India, none of them can be strictly said to be authoritative because in almost every one of them the commentator has expressed his own opinions without touching the spirit of Bhagavad-gītā as it is.
The spirit of Bhagavad-gītā is mentioned in Bhagavad-gītā itself. It is just like this: If we want to take a particular medicine, then we have to follow the directions written on the label.