Fundamentalism, in a religious context, is when a religious group believes that its scripture is the absolute truth, an exact representation of the world, its origins, and/or its eventual fate. Fundamentalism is a sociological movement that is observed in religions other than Christianity. This article deals only with the Christian situation. Christian fundamentalism has its roots in the 1800s. The liberal and conservative strands of Christianity can be traced to the Age of Enlightenment (http://en.wikipedia.org/wiki/Age_of_Enlightenment) in the 1700s. Two major items are believed to have brought about the fundamentalist movement; these are higher biblical criticism (http://www.religioustolerance.org/chr_hcri.htm) as practiced by German scholars since the Enlightenment, and evolution theory as published by Charles Darwin.
Higher Biblical Criticism
A few terms need clarification. These are: higher biblical criticism, and Age of Enlightenment or just Enlightenment. Higher biblical criticism is the study of who wrote the Bible. On the link above to Religious Tolerance (http://www.religioustolerance.org/chr_hcri.htm) there is a fairly good article by B. A. Robinson on biblical criticism. I disagree with Robinson on one point. Robinson says, “Biblical criticism originated with anti-Christian writers who valued reason and logic over faith and revelation.” My problem is with the term “anti-Christian.” I have studied some of the theologians or writers Robinson refers to, and from my perspective as an ex-Christian I think they were every bit as concerned for the true Christian faith as were the fundamentalists. Thus, I disagree that they were anti-Christian; I also disagree that they “valued logic and reason” over “faith and revelation.” The rest of the article looks fine.
The Age of Enlightenment
The Age of Enlightenment, often just called the Enlightenment, lasted from approximately 1750 to 1800. According to the Wikipedia entry on the Enlightenment (http://en.wikipedia.org/wiki/Age_of_Enlightenment), the Enlightenment was a result of the work of people such as Galileo (1564-1642) (http://en.wikipedia.org/wiki/Galileo) and Sir Isaac Newton (1643-1727) (http://en.wikipedia.org/wiki/Isaac_Newton). The Wikipedia entry further says the leaders of the Enlightenment “believed they could lead their states to progress after a long period of tradition, irrationality, superstition, and tyranny which they imputed to the Middle Ages.” In other words, instead of relying uncritically on traditional Christian belief, they believed reason would be a better way to truth. Many of course were Christians and assumed that reason would lead to Christian “truth” .
When Enlightenment thinking was applied to the Bible (higher biblical criticism), it was discovered that Moses probably did not write the Pentateuch (first five books of the Bible), and that most of the prophecies were probably written after the fact. These thinkers analyzed the Bible critically, just like they analyzed other ancient writings such as Homer’s Illiad. For some reason, biblical criticism did not take hold on American soil until after the American Civil War (http://en.wikipedia.org/wiki/American_Civil_War) (1861-1865). Even after the Civil War the former Confederate States resisted biblical criticismup till the 21st Century and they formed the Bible Belt today.
After the American Civil War
After the American Civil War, conservative American theologians became aware of the advances being made by German scholars in biblical criticism. Darwin had published his Origin of the Species (find copy here: http://www.talkorigins.org/faqs/origin.html) in 1859. By 1874, Charles Hodge of Princeton Seminary had published his three-volume Systematic Theology (find copy here: http://www.ccel.org/h/hodge). Hodge argues that the facts in the Bible are for the faith what the facts of nature are for science. Hodge had a powerful impact on conservative Christianity. Because of this, he might well be called the father of Christian fundamentalism.
Scopes Monkey Trial
Fundamentalism came to the fore in 1925 at the Scopes Monkey Trial (http://en.wikipedia.org/wiki/Scopes_Trial). According to the Wikipedia entry, the state of Tennessee passed a law on March 13, 1925 forbidding “any state-funded educational establishment in Tennessee” to teach "any theory that denies the story of the Divine Creation of man as taught in the Bible, and to teach instead that man has descended from a lower order of animals." In other words, teaching evolution was forbidden.
The following paragraph is a direct quote from the article in Wikipedia:
John Scopes, a high school teacher, was arrested for teaching evolution from a chapter in a textbook which showed ideas developed from those set out in Charles Darwin's book The Origin of Species. The famous trial was made infamous by the fictionalized accounts given in the 1955 play Inherit the Wind and 1960 Hollywood motion picture of the same name. END OF QUOTE.
Hidden fundamentalism and re-emergence
According to present-day American scholars such as George M. Marsden (sociologist) and Mark A. Noll (historian), fundamentalism “went underground” for several decades and re-immerged in the last quarter of the twentieth century. Jerry Falwell’s Moral Majority in the 1980s is generally thought to be the formal re-immergence of Christian fundamentalism. Fundamentalism today focuses on three main items commonly called “gay rights,” abortion, and creationism. In other words, Christian fundamentalists are against equal rights for homosexuals—esp. around issues such as marriage, the adoption of children, and in some states the holding of political office. Fundamentalists are also against the teaching of evolution in public schools and against stem-cell research. In addition, they oppose a woman’s choice for an abortion under the argument that life begins at conception and therefore abortion is murder. The same Conservative fundamentalists tend to oppose state funded medical care although the death rate is higher in the United States than in other developed countries with free universal health care. They oppose killing a fetus while it is in the uterus but after a baby is born they are prepared to do less that political liberals do to keep that baby alive.
As stated in the opening sentence of this article, Christian fundamentalists believe that the Bible is the absolute truth, an exact representation of the world, its origins, and/or its eventual fate. However, exactly how this ”truth” looks in everyday life, or how the world actually came into being, and exactly how it will end, are hotly disputed items of theology over which churches can split. While they all agree that the Bible is the inerrant, divinely inspired, infallible Word of God, they disagree sharply on its true meaning.
Literal meaning and metaphor
Whether “true meaning” or “correct interpretation” is the better term is debatable. I opt for the former because, so far as I know, fundamentalists do not accept that interpretation takes place. A thing is what it is; the question for them is whether a statement is meant to be taken literally or spiritually/metaphorically. Though fundamentalists are often accused of taking the Bible literally in all cases, the fact of the matter is that they don’t. The Bible is so ambiguously written, and contains so many internal contradictions, that taking it literally in all cases is impossible. The Bible is not a step-by-step instruction manual and they don’t take it as such. I don’t know whether any formal studies have been done on this, but personal observation suggests that disagreement centers on exactly what portions of the sacred text should be taken literally and what portions should be taken metaphorically or spiritually. Though there is no room to discuss this here, the centuries-long dispute on the appropriate age for baptism—whether infant or believer’s baptism—is one important example of this.
Fundamentalism and morality
Christian fundamentalists are more efective at driving sin underground that at preventing it.
States that banned gay marriage had 11 percent more porn subscribers. The level of agreement in a state with the statement that "Even today miracles are performed by the power of God" predicted higher pornography consumption. States claiming to have old-fashioned values about family and marriage purchased substantially more adult-content subscriptions. 
Why is this? Possible reasons could be that Internet pornography is safe, users can take care that they will not be found out. When someone is sitting by a computer Internet pornography is never more than two or three clicks away. Weak minded people have trouble resisting temptation. The more sexual repression there is in a state or a community the more people are tempted or driven to find whatever outlet they can.
A few books that may lend further insight on the Christian fundamentalist movement are:
Barr, James. "Fundamentalism." London, SCM Press, 1977.
Harding, Susan Friend. "The Book of Jerry Falwell: Fundamentalist Language and Politics." Princeton, NJ, Princeton University Press, 2000.
Marsden, George M. "Fundamentalism and American Culture." New York, Oxford University Press, 1980.
Noll, Mark A. "A History of Christianity in the United States and Canada." Grand Rapids, MI, William B. Eerdmans Publishing Co., 1992.