I reviewed this for Choice.

Ijtihad (Arabic: اجتهاد‎, ʼijtihād) is the making of a decision in Islamic law (sharia) by personal effort (jihad), independently of any school (madhhab) of jurisprudence (fiqh). as opposed to taqlid, following the decisions of a religious expert without necessarily examining the scriptural basis or reasoning of that decision.

To be valid, and accepted it has to be rooted in the Qur'an and the hadith and it is required that no established doctrine rules the case.

Jihad

ijtihad

same root j-h-d

As defined by Amira K. Bennison, "the legal technique of using independent reasoning to derive legal opinions" (p. 164).

Jamal al-Din al-Afghani failed to move towards a modern Muslim Enlightenment although he took Western ideas seriously and honestly grappled with their implications.

Muhammed Rashid Rida did not call for the revolutionary establishment of an "Islamic state" itself, rather advocating only gradual reform of the existing Ottoman government, Rida preceded Abul Ala Maududi, Sayyid Qutb, and later Islamists in declaring adherence to Sharia law as essential for Islam and Muslims.

Both of these individuals failed to grasp that Islam needed reform to truly enter the modern world.

The Islamists won out: the Muslim Brotherhood, Sayyid Qutb, and of course Osama bin Laden.