Yogi Ramacharaka 
Lessons in Raja Yoga [PDF ebook] 

’Yogi Ramacharaka’ was the pen name of William Walker Atkinson, an American attorney, businessman, and author who was instrumental in introducing the concepts of yoga to the West in the nineteenth century. "Raja" yoga is the branch of the practice that addresses the nature of the mind, and imparts techniques to help better manage and control one’s mind through meditation and other methods. Yoga enthusiasts and those interested in the spread of Eastern spiritual practices in the West will appreciate this detailed take on the subject.