What do you disagree with? Be specific.
I disagree with the premise that Hesychasm has any roots in Hinduism or Buddhism. Bishop Kallitos TRANSLATED the Philokalia. He didn't write it. I own most of the volumes and they are chalked full of scripture.
It is a method of prayer. Didn't Jesus say not to pray like the hypocrites. I am sure you don't understand Hesychasm, and neither did your author.
This is a good response to Calvinist's efforts to defame Byzantine Christianity:
http://www.orthodoxinfo.com/inquirers/thema_response.aspx