I think micro finance is largely undercut by the claims made about it in the 2000s. But if it's an important issue for you maybe it's worth reading the linked book (https://www.amazon.com/exec/obidos/ASIN/1609945182/)? The reviews seem fairly positive.
The primary research it's based on: https://www.aeaweb.org/articles?id=10.1257/app.20140287
I think micro finance is largely undercut by the claims made about it in the 2000s. But if it's an important issue for you maybe it's worth reading the linked book (https://www.amazon.com/exec/obidos/ASIN/1609945182/)? The reviews seem fairly positive.