Start with high-confidence sunni islam books, then narrow by subgenre or adjacent topics.
Theology and Creed in Sunni Islam
J. Halverson, Jeffry R. Halverson
Messianic Ideas and Movements in Sunni Islam
Yohanan Friedmann
The Life of Ibn Ḥanbal
Ibn al-Jawzī, Michael Cooperson
Understanding Salafism
Yasir Qadhi
From God's Nature to God's Law
Abdul Rahman Mustafa
