The Book of Ruth in Easton's Bible Dictionary

was originally a part of the Book of Judges, but it now forms one of the twenty-four separate books of the Hebrew Bible. The history it contains refers to a period perhaps about one hundred and twenty-six years before the birth of David. It gives (1) an account of Naomi's going to Moab with her husband, Elimelech, and of her subsequent return to Bethlehem with her daughter-in-law; (2) the marriage of Boaz and Ruth; and (3) the birth of Obed, of whom David sprang. The author of this book was probably Samuel, according to Jewish tradition. "Brief as this book is, and simple as is its story, it is remarkably rich in examples of faith, patience, industry, and kindness, nor less so in indications of the care which God takes of those who put their trust in him."

Link: https://bible-history.com/eastons/R/Ruth+The+Book+of/