The key element in leading a life which is successful is literacy. Literacy is important in all levels of employment. For people who literacy is not available to, different reasons push them to become literate. Literacy is a social unifier.
A person is more effective in completing daily tasks, more efficient in their work, and is considered to be a much more powerful person amongst their peers when literate. Doors open much more easily for people who are literate. For example, who is going to hire an individual who can not even properly fill out a job application? It does not shy nice on the job you are applying for.
In some job fields it is easier to see why you would need to be literate, such as being a reporter for a newspaper. You would obviously need to know how to read and write above the level of most others to become successful.
Also a doctor would need literacy to get through years of college to become even adequate in his area. In a position such as a worker in a phosphate plant you may not be able to see why you would need literacy to do your job, but I have an argument for that. Say you are trying to operate a new piece of machinery and there is no one around to read the manual for you. In this situation, you are going to be unsuccessful in completing your simple job description.
For people whom literacy is not valued, passion is a big factor for them to search it out. Take Frederick Douglas; was just another slave on the plantation, but the difference between him and the other slaves was that he had passion. Douglas had a passion to learn the...