Christianity's Dangerous Idea

These days, I am reading a book, 'Christianity's Dangerous Idea' written by Alister Mcgrath. this book has fully 900 pages, but comparatively easy to read.
  This book is all about protestantism's history and 'Dangerous Idea' is about protestantism idea. Mcgrath says protestantism contains fatal danger because of its subjectivity in hermeneutics. After religious reformation, because of its huge effect, lots of people started to believe they can interpret the text themselves. (before religious reformation, idea like this was totally beyond imagination because bible interpretation was fully in charge of the Church and people thoroughly depend on church's interpretation) and unfortunately this idea, nowadays, gave birth to many ideas, denominations, ridiculous heresies and irreparable conflicts.
  To explain protestantism's history and development of this Idea and make an anticipation, Mcgrath start from 16c religious reformation. His explanation is concise, ample, outstanding. I am big fan of him, enthusiastic student. Although i read only 100 pages now, I fall for him and fall into debt to him. To me, everything is unfamiliar and staggering. You know what? Luther didn't against purgatory itself! He just opposes idea that Pope can reduce the period how someone have to stay in purgatory. And he never wanted to make a new religious!