The Quran has been heavily scrutinized like other religious scriptures. Its study has become more prominent in "western" academia especially so in the last thirty years or so, although there is a long tradition of study by Islamic theologians and scholars basically since the birth of the text.

It is important, however, to contextualize the term scripture. The Quran is said to have been recited orally by Muhammad over a period of time. Each chapter or sura was divinely inspired,and received by Muhammad as relevant to a certain time or place. Tradition holds that the Quran was only compiled in writing in the time of the third caliph, Uthman. Indeed, the order of chapters of the written Quran is not the same as the order in which the suras were revealed to Muhammad.

Thus, the Quran was not "written" in the same way that the bible was written. Quran literally means "recitation" so strictly speaking it wasn't written so much as transcribed.

All of this, however, is according to tradition and some historians disagree with the narrative of how a written Quran came to be.

Edit: part of the body of Islamic religious "text" and tradition are the hadith. The hadith are collections of sayings according to the prophet Muhammad. They are said to be learned sayings rather than the divine revelation of the Quran and were never compiled as such. Unlike the Quran, the hadith are more heavily contested about whether or not they are legitimate, what was their context, whether they are accepted as true. Thus different branches of Islam may accept different hadiths.

I apologize for the delay in providing sources, I was traveling all day yesterday and then slept half of today away. Sources and further reading: Approaching the Qur'an, Sells; The Cambridge Companion to the Qur'an, McAuliffe; The Qur'an: A new annotated translation, Droge; Before Islam, Safi; God and Man in the Quran, Izutsu

We have some idea of who wrote the old testament? I thought we had no idea about most of those books.