Christianity is a faith tradition whose primary object of focus is Jesus Christ.  It is one of the most widely spread and well publicised religions of the modern age.  Through the years, Christianity has been responsible for giving the world some of the most amazing, dedicated and selfless people that the world will ever see, (Gandhi and Mother Theresa, instantly come to mind) and some of the most horrendous and bloody religious warfare we hope the world will ever see.
The first Christians were Jews as was Jesus, and they practised monotheism, or the worship of One True God.  As with most religious groups, their primary objective was the search for Truth, which ultimately was God.  It was the essence of the Christian tradition to reject all other Gods and ways, insisting that they were united in their devotion to the essence, which is valourous, but also can be blamed for the mass religious genocide that this narrow way of thinking affords a group.

The early Christians did do one interesting thing which is kind of unique, they adopted the canons and God of the Hebrews to help them explain how they could be monotheists and still worship Christ, who was God's son, according to tradition.  This is why modern Christians are sometimes referred to as Judaeo-Christians, because Judaism is the religion of the early Hebrews who did not accept Christ as their Saviour.  This is interesting because not many religious groups have done it and later Christians, basically just kill anyone who disagrees with them and happily pass the recently deceased groups traditions off as their own in future generations.
History of Christianity
The Bible is the basic reference guide for Christians.  It is broken into two major divisions, the Old and New Testaments.  The Old Testament is pretty heavy going in places and was mostly taken from the mythology of the Hebrews and speaks of the all powerful God of Israel whom the Hebrews worshipped.  The New Testament is the story of Jesus as taken from his various followers or disciples and some letters and articles written by these followers after Christ's death.
The Bible
Regardless of whether Christianity is the religion you choose, the Bible is worth a read.  It contains some great historical and mythological information, much of which has been taken from other religions and packaged slightly more cohesively.  King Solomon, one of the most well known magi of the BC era, covering his bets worshipped the God of the Israelites for a while and gave the Bible a fantastic chapter called Proverbs.  Many of these "words of wisdom" have been adopted into our common language as simple reminders of common sense.  For example, sayings such as, "Good things come to those who wait" and "You reap what you sow" all have their basis in Proverbs.

In the New Testament, Jesus comes along and teaches similar values to those that Solomon was attempting to teach his son with parables.  Parables are cute, little anecdotal stories that have a moral, like Aesop's Fables, but usually with less animals.
The Apostles' Creed
The Apostles' Creed is a good place to start if you would like to understand what modern Christians believe in.  It was developed somewhere between the second and ninth centuries as an affirmation of faith for Western Christians. 

In summing up, Christianity is a very dogmatic religion, lots of thou shouldst and thou shouldnsts all over the place, but it still has a lot to teach humanity.  Effectively, Jesus Christ, or the myth that was created under the name Christ was a pretty good bloke and certainly had his heart in the right place if we are to believe the stories of the Bible.
For further information or to email Josephine directly.