The Book of Joshua in Easton's Bible Dictionary

contains a history of the Israelites from the death of Moses to that of Joshua. It consists of three parts: (1.) The history of the conquest of the land (1-12). (2.) The allotment of the land to the different tribes, with the appointment of cities of refuge, the provision for the Levites (13-22), and the dismissal of the eastern tribes to their homes. This section has been compared to the Domesday Book of the Norman conquest. (3.) The farewell addresses of Joshua, with an account of his death (23, 24). This book stands first in the second of the three sections, (1) the Law, (2) the Prophets, (3) the "other writings" = Hagiographa, into which the Jewish Church divided the Old Testament. There is every reason for concluding that the uniform tradition of the Jews is correct when they assign the authorship of the book to Joshua, all except the concluding section; the last verses (24:29-33) were added by some other hand. There are two difficulties connected with this book which have given rise to much discussion, (1.) The miracle of the standing still of the sun and moon on Gibeon. The record of it occurs in Joshua's impassioned prayer of faith, as quoted (Josh. 10:12-15) from the "Book of Jasher" (q.v.). There are many explanations given of these words. They need, however, present no difficulty if we believe in the possibility of God's miraculous interposition in behalf of his people. Whether it was caused by the refraction of the light, or how, we know not. (2.) Another difficulty arises out of the command given by God utterly to exterminate the Canaanites. "Shall not the Judge of all the earth do right?" It is enough that Joshua clearly knew that this was the will of God, who employs his terrible agencies, famine, pestilence, and war, in the righteous government of this world. The Canaanites had sunk into a state of immorality and corruption so foul and degrading that they had to be rooted out of the land with the edge of the sword. "The Israelites' sword, in its bloodiest executions, wrought a work of mercy for all the countries of the earth to the very end of the world."...

Link: https://bible-history.com/eastons/J/Joshua,+The+Book+of/