Well, we raced through this topic in class so here are some books for you to pore over (click on the titles to download the book):
1) Faith in the Angels – Shawana Aziz
This is a nice book, basic but with plenty of information. May Allah reward this sister for her great work.
I’d advise everyone to check her website as well: http://www.qsep.com. There’s lots of great stuff there.
2) Belief in the Angels and Its Effect on the Life of this Ummah – Shaikh Saalih Al-Fawzan
This is the book that I mentioned in class.
3) Belief in the Angels – Sameh Strauch.
You can read it online here: http://abdurrahman.org/faith/beliefintheangels.html
There’s also a nice lecture on this topic. It’s based on Umar Al-Ashqar’s book “The World of the Noble Angels”.
Angels By Yasir Qadhi (Download):