Books Beneficial for Buddhist to Study

Question: 

What kind of Sutra or Mantra or Buddhism Reference books beneficial for us to study?

Answer: 

i)    Any teaching that say one must do rituals so that the person will have a better chance of salvation and go to Heaven is not beneficial.

ii)   Any teaching that say if one do not believe it then one will go to Hell is not beneficial.

iii)  Any teaching that say the World is evil and we are born here to suffer and one must believe them so that they will go to Heaven is not beneficial.