Yogani's most recent book "Samyama - Stillness in Action, Siddhis and Miracles" has the most thorough coverage of this ancient Yoga technique that I have found. It can be practiced successfully with just a slight emergence of inner silence, which is cultivated by deep meditation, described in an earlier book of his popular Enlightenment Series. The time one needs to set aside daily is very minor, only about 10 minutes or less, and could therefore fit into anybody's schedule.
Samyama could be seen as a crystallization in the outer world of the practitioner of the inner stability and harmony gained through meditation. The implications of this process are huge, even if one only sees it as one's life coming into more order, but often people talk about miracles happening in their lives as well. Yogani doesn't stop, however, with just describing the technique itself, how to practice it and how it works. Another very important aspect of Samyama, as with all Yoga practice, is the science of self-pacing. He teaches us in detail how to moderate our practice to avoid getting too much too soon, which could be overwhelming.
Considering the small size of the book (only about 100 pages), it goes even further however, to go into Samyama and its relation to the rise of the Active Witness, Yoga Nidra, Asanas (yoga postures), the Samyama Sutras of Patanjali, relationship of inner silence and ecstasy, and finally Enlightenment. I would much recommend it!