1. No need to read this Grantham. There are several books to be read in our sampradayam. Not why this query was raised.
2. Swami Desikan provided a simple explanation – it is evident when we say ‘My body, My hand, My leg, etc.’ that the physical body and I/ME (Soul) are different. Particularly, when asleep, there is no thought of body, but there is a consciousness about the Atma. In this way, one can realize the difference between body and soul.
We can carry out physical chores only through a physical body; we must avoid the perplexity that arises when we consider that I/ME as a physical body, and have the knowledge that I/Me is separate from the physical body.
Swami Desikan has said that when one disparages the physical body by saying that you are dark, one must realize that this does not affect the Atma; and this thought will enable one to stay calm and avoid getting angry.
3. For this, Swami Desikan has composed a drama called Sankalpa Suryodayam. In it, he says that by cultivating proper knowledge, detachment, Vishnu Bhakti, etc., one can reduce bad manners; he also says that being in the sanctum of Bhagavan, close association with Bhagavata-s, kalakshepam, etc. are important. Desikan says that when one is angry, one must pause and think calmly that the person about whom one is angry is not the direct cause of the anger; and that we are the cause and others indirectly cause our anger; similarly, one is jealous when one forgets about one’s shortcomings; when we think about our defects, we will not be jealous.
Desires can be conquered through wisdom. All of these are found in the Sanklapa Suryodayam drama.