Beryl Bender Birch is the bestselling author of Power Yoga, Beyond Power Yoga, and Boomer Yoga; she is also one of the most popular yoga teachers in the United States. With degrees in philosophy and comparative religion, Beryl has been teaching the classical system of ashtanga yoga for 33 years, and training yoga teachers as "spiritual revolutionaries" since 1980. In 2000 she was named by Yoga Journal as one of their “Innovators Shaping Yoga Today” issue.

Beryl majored in philosophy and comparative religion at Syracuse University. She took her first yoga class in 1971 in California. She then spent several years on the West Coast working as a biofeedback researcher and studying the physiology of meditation. One of her early teachers was Chogyam Trungpa Rinpoche, the Tibetan Buddhist who founded Naropa University in Boulder, Colorado, as well as Shambhala International. Her other important teacher was Munishree Chitrabhanuhu, the first Jain monk to leave India and come to the United States at the invitation of Harvard Divinity School. These two men shaped her life, her meditation practice, and her teaching style.

In 1974, Beryl began to teach yoga and meditation to skiers in Winter Park, Colorado, working with both professional and recreational skiers. In 1980, she moved to New York City and was introduced to the practice of ashtanga yoga by Norman Allen. Allen was Sri K. Pattabhi Jois's first American student and the first Westerner to master the ashtanga series and bring it to the United States.

In 1981, Beryl began teaching ashtanga yoga to runners at the prestigious New York Road Runners Club, and eventually she became the club's wellness director. Beryl and her husband Thom, a world-class runner, pioneered the introduction of yoga to the traditional athletic community. Together Beryl and Thom taught the ashtanga yoga method of asana, pranayama, and dharana (concentration) to tens of thousands of students.

In the late '80s, Beryl was searching for a way to make ashtanga yoga more accessible to American students, and she coined the term "power yoga" (nearly simultaneously, Bryan Kest, based in Los Angeles, came up with the same term.) The words "power yoga" convey the distinction between the intense, flowing style of yoga Beryl and Thom were teaching from the gentle stretching and meditation that many Americans associated with yoga. Power yoga is a vigorous, fitness-based approach to yoga.

In 1987, Beryl traveled to Feathered Pipe Ranch in Helena, Montana, to meet and study with Sri K. Pattabhi Jois, the principle proponent of the ashtanga yoga vinyasa method, and the teacher with whom Norman Allen had studied. Beryl and Thom spent the next six months studying daily with Jois and following his tour of California. They continued their studies with Pattabhi Jois from 1987–1990.

Beryl is the founder and director of The Hard & the Soft Yoga Institute (since 1980) in East Hampton and Vermont, and a founder of the Give Back Yoga Foundation. She now teaches yoga—the Middle Path of Jina Yoga (incorporating the classical astanga eight-limbed methodology)—all over the world, guiding and inspiring students of all levels with her down-to-earth style. She currently writes the asana column for Yoga Journal. She resides in East Hampton with her six racing Siberian huskies, and she competes on the New England Sled Dog Club circuit of sprint races in Vermont, New York, and New Hampshire.