What would be the condition of Muslims before the arrival of Imam Mahdi (AS) and is there any authentic book on this topic?

MuslimsImam al-Mahdi
What would be the condition of Muslims before the arrival of Imam Mahdi (AS) and is there any authentic book on this topic?
Mateen Charbonneau, Sheikh Mateen Joshua Charbonneau achieved a certificate from Harvard University in Islamic Studies. He undertook Howza classes under esteemed scholars since 2013 and has been teaching at Imam Mahdi... Answered 5 years ago

There is a very beneficial video series about the topic here:

https://youtube.com/playlist?list=PLD2F0DFA18BFBD747