The Role of Christian Beliefs

Before talking about specific beliefs, it's probably worth saying something about the role of beliefs in Christianity. Christianity tends to put more importance on proper belief than many other religions. The term "orthodox" (from roots meaning "right belief") is used to describe beliefs that are in agreement with the standards set up by the Christian community.
When you say that someone is a Christian, you normally mean that he accepts the major Christian beliefs. That's not the whole story, since Christianity is also a way of life and a community. But most Christians do not think it is appropriate to apply the term Christian based simply on the fact that someone has Christian parents and grew up as a Christian, or even based on the fact that they admire many of Jesus' teachings. To be classified as a Christian, one is normally expected to accept the major Christian beliefs, to be following the way of life that Jesus taught, and to be a part of the Christian community.
Most Christian groups have standards of belief. Members are expected to accept the standards of their community. This is not to say that Christians have no questions or doubts. Most groups (even fairly rigid ones) permit members to express uncertainty and to question beliefs. However most groups expect leaders and teachers to advocate orthodox positions. Groups differ both in the way their standards are codified, and in the degree of conformity that they expect. Some have detailed formal standards of belief. Others use only the Bible, and allow a good deal of variation in interpretation.
This document will tend to emphasize beliefs. It's worth noting that this emphasis may be misleading, both about what Jesus originally taught and about what it is like to be a Christian. The most controversial aspects of Christianity -- and those that are emphasized in presentations of Christianity -- tend to be beliefs, particularly beliefs about Jesus. However Jesus' teachings were primarily about how his followers should live. It is these teachings that form the heart of Christian life for most Christians. Unfortunately they are hard to summarize. They are also less commonly talked about in Christian discussion groups, largely because they are less controversial. That's why I have advised people who are interested in Christianity to read at least one of the Gospels in addition to (indeed before) this document. The Gospels are made up primarily of Jesus' teachings, as well as narratives about his life.