How does a shared library work?

[Tshepang Lekhonkhobe]

Hello,
I wanted to avoid some searching headache by asking this question here:
I hear that the advantage of shared libraries is that there's only one
copy of that library in memory and I assume that the library is loaded
in memory only the first moment that a dependant package is run. But
who's reponsible for making sure whose turn it is to use that library
in case of several dependant packages requiring its use? Is it the
kernel?

malebo