QOS and Security Study

Guys,

Where should i study QOS and Security from? and what should be my plan of
action (Just for Theory part)... Should i take a book like QOS Exam guide
and read it cover to cover? or should i just take 1 topic from 4.0 Blueprint
at a time and use 2 3 resources(e.g DOC CD ) to understand that topic
only.... also to what extent should we use DOC Cd to learn topics like
QOS,Security and Mcast....

-- 
Regards,
Asif Khan
Blogs and organic groups at http://www.ccie.net