In a good spiritual path, you need to have techniques that will not only get your body/mind ready to experience bliss and ecstasy and stillness, but also techniques to transcend the mind and use the the stillness and energy cultivated in practices to move higher in our spiritual journey.
Yogani has 2 volumes of "Easy Lessons For Ecstatic Living" books available. The first one is a book providing instruction in the core yoga techniques that can be used to bring the body/mind to a state of readiness for higher spiritual techniques. These include deep meditation, spinal breathing pranayama, asanas, mudras, bandhas, tantric sexual methods, samyama and others.
The second volume covers:
1) Many techniques to use the stillness cultivated through the basic yoga techniques in prayer, self inquiry, and other practical applications.
2) Many other enhancements to make the basic techniques taught in the first volume more effective.
3) Volume 2 also expands and gives details on the shatkarma techniques that were only introduced in the first volume.
4) Additional explanations on physical and psychological experiences that are brought on by an active kundalini, and how to manage them. The functions of soma, amrita and ojas are explained
5) The various stages of the mind and how and when to engage in self inquiry
I would highly recommend getting this book if you want to develop the advanced stages of spiritual development. The two AYP Volumes cover a lot of information that you may finally have to buy many books to get, and in some cases not find anywhere else in writing.