You might be interested in perusing Aleister Crowley's magnum opus Magick, Liber ABA, Book 4.
Crowley was a colourful character, as a quick glance at his Wikipedia page will tell you. Part I of Book 4 contains a distillation of Crowley's understanding of yoga and meditation. He borrows heavily from Patanjali and Yagnavalkya but strips away all of the "mysticism" that he sees in them.
I leave it to you to decide if it holds any value as a guide on yoga and meditation, though.
Summary on Goodreads:
BOOK FOUR, Parts I and II, together with Magick in Theory and Practice (which is Part III of BOOK FOUR) make up a complete course in Magick, with practical instruction in Yoga and mysticism.
This book is the introduction, the foundation upon which all further magical work will be based. Its simplicity, clarity and depth is without equal in occult literature.
The first part of BOOK FOUR deals with Yoga in a very sound and methodical manner, stripping it of the mysterious and glitter. Soberly, Crowley describes each step as a technique of mental and/or physical discipline, ultimately resulting in complete control of the will and with this, control of the physical and mental body.
Crowley speaks with authority as he is one of the few writers on the subject of Yoga and Magick who has attained Dhyana and Conversation with his Holy Guardian Angel through discipline and ritual practices.
The second part of BOOK FOUR is an encyclopedia of magical symbolism, the working tools in practical magic. All of the paraphernalia employed in ritual magic are carefully explained in both psychological and mystical terms.
The Wand is the will of man, his wisdom, and his word; the Cup is man's understanding, the vehicle of grace; the Sword is reason, the analytical faculty of man; and the Pantacle is man's body, the temple of the Holy Ghost. All phenomena are sacraments. Every fact must enter into the Pantacle. It is the great storehouse from which the Magician draws.
The laws and truths of the occult world which are presented here give the student a sound working knowledge and set him firmly on the path. BOOK FOUR is a concise, direct and honest presentation.