[newbie] what are the cd's for?

[srinivas sastry]

hi         i'm new to linux . i bought mandrake power pack 7.2 deluxe box . i could  install it using the first four cd's ( number 1 to 4 ).  i want to know what  the cd's numbered 5 to 7 are for? ( they are of no use while installing ).          also where in those cd's do i have to look for linux books (  e-books ) and how?          please help.          thanks          sastry