What is the ruling on working for a company that deals with usurious banks or deposits its money in them? And is it permissible to work in a public library that contains books of non-Islamic religions and books of the people of innovation?

It is not permissible to work in a library that contains deviant books unless the general public is safeguarded from accessing them. If it is possible to provide these books to those firmly grounded in knowledge who are capable of refuting misconceptions, then it is permissible and will be rewarded. Otherwise, it is not permissible to work there for fear of corrupting the beliefs of the general public.