Quran Introduction

Quran Revelation
Holy Quran is the book of Allah revealed to the last Prophet Muhammed (PBUB).  Quran revelation took 22 years, it started in 610 A.D and continued till 632 A.D. Surah Alq first 5 ayeas revealed and then 3 years gap. Almost all of the Quran was revealed in Hijaz (Mecca, Medina and surrounding areas). 
Except two ayas (last two ayas of Surah Al-Baqara) were reveled during Meeraj at seventh heaven. 

Quran is the message of Allah and He guaranteed to protect it from any kind of changes as mentioned in   Surah Al-Hijr ayat 9
"We have, without doubt, sent down the Message; and We will assuredly guard it (from corruption)." 15:09