You are strongly recommended to add to your library the excellent revised edition of Harper's Bible Dictionary titled, The Harper Collins Bible Dictionary, Revised Edition, edited by Paul J. Achtemeier, with the Society of Biblical Literature (NY: Harper Collins, 1996). It is currently the best one-volume Bible dictionary in English, and it is available at Border's Books, Christian Science Reading Rooms, http://www.borders.com, or http://www.christianbook.com.

Jethro, Moses’ father-in-law, ‘the priest of Midian’ (Exod. 3:1). The Hebrew form is ytrw in the Masoretic Text (except for Exod. 4:18, ytr, Jether) and in the Samaritan Pentateuch; the Septuagint has Iothor throughout. Jether occurs elsewhere for the father of Amasa and for sons of Gideon, Jada, Ezrah, and Zophah; related names include Jattir, Jithrite (Ithrite), Jithran (Ithran), and Jithream (Ithream). Jethro, however, is reserved for Moses’ Midianite father-in-law. He cared for Moses’ wife and sons during the Exodus; afterwards, he suggested a more effective structure for Moses’ governance of the people (Exod. 18). His relationships with Reuel (Exod. 2:18) and with Hobab (Num. 10:29; Judg. 4:11) are unclear. If Reuel were Jethro’s father and Zipporah’s grandfather, Hobab could either be Reuel’s son, Jethro’s (half-)brother, and Zipporah’s uncle, or Reuel’s grandson, Zipporah’s (half-)brother, and Jethro’s son or nephew. Less likely is the suggestion that Reuel is the clan name of both Jethro and Hobab.