Catechesis consists of intentional, orderly instruction in the truths that Christians are called to live by-a sort of discipleship in mere Christianity. The fact that catechesis has fallen out of the curriculum of most churches today is a major loss, leaving many Christians under-nourished and spiritually sluggish. Professor J. I. Packer, one of the most influential evangelicals in America today, claims catechesis is of the utmost importance in developing an ecumenical church that maintains orthodox beliefs. Packer's newest book pushes Christians to know their faith so they can explain it to inquirers and sustain it against skeptics, and can put it to work in evangelism, church fellowship, and the many forms of service-this is the Christian's business of taking God seriously.