In 1992 there was the Live Forever a.k.a. Paradise book (full title You Can Live Forever in Paradise on Earth), released 1982, revised 1989. It was used as the primary Bible study aid until 1995, when the Knowledge book (Knowledge That Leads to Everlasting Life) was released. The Knowledge book was eventually superseded by the current Bible Teach book (What Does the Bible Really Teach?), published in 2005 with two illustrations updated in the 2006 reprint.
After completing this first Bible study aid, the student (even if baptized by the time they finished this first book) would go on studying a second book. Indeed in the '80s and up to 2002 this was the United in Worship of the Only True God, released in 1983. This book was reedited with some significant changes and published as Worship the Only True God to be released at the 2002 district conventions. The current book on Christian conduct and principles regarding this is called "Keep Yourselves in God's Love", released in 2008.
Starting 1996-1997, some would start a Bible study using the What Does God Require of Us? brochure (this Require brochure was released in 1996) before heading to the first study aid. This role will be taken next year by the brochure released this year and titled Good News From God!