Had a peak at the wiki entry:

The Book of Joshua (Hebrew: סֵפֶר יְהוֹשֻׁעַ Sefer Yəhōšūaʿ, Tiberian: Sēp̄er Yŏhōšūaʿ; Greek: Ιησούς του Ναυή; Latin: Liber Iosue) is the sixth book in the Hebrew Bible and the Old Testament, and is the first book of the Deuteronomistic history, the story of Israel from the conquest of Canaan to the Babylonian exile.  It tells of the campaigns of the Israelites in central, southern and northern Canaan, the destruction of their enemies, and the division of the land among the Twelve Tribes, framed by two set-piece speeches, the first by God commanding the conquest of the land, and, at the end, the second by Joshua warning of the need for faithful observance of the Law (torah) revealed to Moses.

Yeah, I was reading a lot about Jesus and the early church (atheist, history nerd), and I pretty much came away thinking that the ancient Jewish texts are pretty brutal.