The ▁Hard ▁& ▁the ▁So ft ▁Ast anga ▁Y oga ▁Institute ". ▁ ▁Re ception ▁ ▁Publish ers ▁Week ly ▁writes ▁that ▁some ▁readers ▁" may ▁find ▁Power ▁Y oga ▁narrow ly ▁pres cript ive ▁or ▁severe . ▁However , ▁Bir ch ' s ▁cred ibility ▁supports ▁her ▁passion ate ▁advoc acy . ▁This ▁is ▁an ▁important ▁book ▁for ▁the ▁y oga ▁community , ▁as ▁well : ▁a ▁thought ful ▁ex position ▁of ▁one ▁of ▁several ▁major ▁y oga ▁movements ▁that ▁have ▁developed ▁from ▁the ▁work ▁of ▁Kr ish nam ach ary a , ▁one ▁of ▁this ▁century ' s ▁great ▁y og is ." ▁ ▁K ali ▁Om , ▁writing ▁on ▁Y oga ▁Chicago , ▁describes ▁Bir ch ' s ▁writing ▁style ▁as ▁never ▁d ull , ▁with ▁hum our ▁and ▁a ▁cheer ful ▁tone , ▁but ▁cas ual ▁and ▁with ▁" end less ▁an ec d otes ". ▁She ▁finds ▁the ▁account ▁of ▁the ▁as ht anga ▁primary ▁series ▁in ▁Bey ond ▁Power ▁Y oga ▁cond ensed ▁and ▁" s ometimes ▁confusing ", ▁but ▁writes ▁that ▁the ▁book ▁provides ▁a ▁non - th re aten ing ▁introduction ▁to ▁the ▁seven ▁other ▁lim bs ▁of ▁as ht anga ▁y oga ▁beyond ▁the ▁physical . ▁ ▁Works ▁▁▁ 1 9 9 5 ▁Power ▁Y oga , ▁At ria . ▁▁▁ 2 0 0 0 ▁Bey ond ▁Power ▁Y oga : ▁E ight ▁Level s ▁of ▁Pract ice ▁for ▁Body ▁and ▁Soul , ▁Touch stone . ▁▁▁ 2 0 0 9 ▁Bo omer ▁Y