The use of ‘few’, ‘a few’’ and ‘the few’ should be used with care. They denote ‘number’.
1. ‘Few’ means ‘not many’, ‘almost nothing’.
2. A ‘few’ is positive and means ‘some at least’.
3. ‘The few’ means ‘whatever there is’

Example :
1. A few men are free from fault. (Incorrect)
Few men are free from fault. (Correct)

2. Few teams will qualify for the world cup. (Incorrect)
A few boys will pass in the examination. (Correct)

3. I have already read a few books that are in the library.
(Incorrect)
I have already read the few books that are in the library.
(Correct)