This is a Madani Surah and it was most probably revealed in the first year of Hijrah before the battle of Badr.  This Surah has 38 verses in 4 sections.

The Surah talks about the real struggle that will take place between the truth and falsehood.  In this struggle the truth will be victorious and the falsehood and its followers will be utterly defeated.  The separation will take place between those who believe and those who will deny the truth.

Recitation: Shaykh Mishaari Raashid & Ibrahaim Walk using Saheeh International Translation. Thematic introduction: Dr. Muzammil H. Siddiqi.