The best translation and commentary on this is by Rabbi Aryeh Kaplan. It includes the complete Hebrew text of all versions of this book, a clear commentary with generous commentary and explanation, and in depth discussions of many areas of Kabbalah with clear and lucid explanations and diagrams. The first commentaries on this book were written in the 10th century, and the text itself is quoted as early as the sixth century. So ancient is this book that its origins are no longer accessible to historians.
Careful study indicates that it is a meditative text with magical overtones.
The Sefer Yetzirah is a small and concise book, only 1300 words long in the short version and 2500 words long in the long version. To guide the novice, Rabbi Kaplan takes great care to introduce the necessary knowledge to the reader, making it accessible for the very first time to English speakers without a Kabbalistic background.