Question Summary:
Is reading social improvement books contrary to religion

Question Detail:

As-salamualaikum,
i would like to know whether reading "How To Win Friends And Influence People, written By Dale Carnegie" and applying those tactics in our day to day life would cast me out of religion.
I heard an incident when Hazrath Umar Raziallahuunhu came up with few papers that belongs to the deeds of Hazrath Musa alaihis salaam and Hazrat Muhammed Sallallahu alaihe wasallam got angry and said if HAzrath Musa Alaihis salaam happen to come in my time he has no other way than fo follow my path. 

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
Shariah emphasizes on being friendly and sociable.[1] Accordingly, one may read related books to inculcate such skills in him.
We advise against inculcating such skill through non-Muslim sources. Reading has a stealthy effect on a reader who could be influenced by the author through the strong writing effect. There is enough Islamic literature available to inculcate friendly and social skills in a person.
The Hadith in reference[2] is not analogous as it refers to the Towrah which was tampered with. The silence of Rasulullah (صلى الله عليه وسلم) could be taken as an absolute endorsement of the advices of the Towrah. Furthermore, it was disrespectful to refer to the Towrah in the presence of Rasulullah (صلى الله عليه وسلم) who is the greatest Prophet upon whom the Quran, the greatest book was revealed.
And Allah Ta’āla Knows Best
Saad Haque
Student Darul Iftaa
New Jersey, USA 
Checked and Approved by,
Mufti Ebrahim Desai.