The traditional view in Judaism and Christianity is that Moses wrote the Book of Leviticus along with the other four books that comprise the Torah and Old Testament: Genesis, Exodus, Numbers and Deuteronomy. The only exception is the final eight verses of Deuteronomy, which concern Moses' death and burial.
Bible scholars debate the time period that Leviticus was compiled, but the range of 700 to 500 B.C. is often given. In general, the book is written as a codification of the ritual, moral and legal practices concerning proper conduct when worshipping God. Most scholars agree that the content of the book indicates significant editing throughout its history.