[Hoglaunccoolf]

There are many books written on the subject
One of the good one is Differences of Imam, White thread Publication (relation between hadith and derivation of shariah from the sources i.e quran, Sunnah etc).
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The legal status of madhab by Mufti Taqi, available on the net
http://www.central-mosque.com/index....-a-madhab.html

Please see the following link as it is formulated to assists reverts
http://www.sunniforum.com/forum/show...s-Please-Reply

To be honest following a school in essense is a must out of necessties as none of us are qualified in any relegious sciences. Hence vast majority of the scholars if not all regardless of their speciality opted to follow.
The only exception is current times where shallow superfical slogan used to fool people.
This is one of the way the orientalist attampts to breakdown the wall of Shariah.
Allahualam