Grammar usage

Natalie's answer perpetuates a myth about English usage and style that has long between held by elementary and high school teachers.

Garner's Modern American Usage (3rd edition, 2009, Oxford University Press) strives to be to American usage what Fowler's has long been to British usage -- the definitive guide. Garner's has this to say about "and":

"It is rank superstition that this coordinating conjunction cannot properly begin a sentence. School teachers may have laid down a prohibition against the initial and to counteract elementary-school students' tendency to begin every sentence with and. As Follet and Amis point out, the same superstition has plagued but. The very best writers find occasion to begin sentences with and."

Garner's goes on to provide a half page of noted examples.

The Chicago Manual of Style (16th edition, 2010, University of Chicago) is the most widely used American style guide for publishing and one of several popular style guides used for academic papers. It tells us (at 5.206):

"There is a widespread belief -- one with no historical or grammatical foundation -- that it is an error to begin a sentence with a conjunction such as and, but, or so. In fact, a substantial percentage (often as many as 10 percent) of the sentences in first-rate writing begin with conjunctions. It has been so for centuries, and even the most conservative grammarians have followed this practice. Charles Allen Lloyd's 1938 words fairly sum up the situation as it stands even today:

"Next to the groundless notion that it is incorrect to end an English sentence with a preposition, perhaps the most wide-spread of the many false beliefs about the use of our language is the equally groundless notion that it is incorrect to begin one with "but" or "and." As in the case of the superstition about the prepositional ending, no textbook supports it, but apparently about half of our teachers of English go out of their way to handicap their pupils by inculcating it. One cannot help wondering whether those who teach such a monstrous doctrine ever read any English themselves."

Many other highly regarded style guides do not address the issue at all -- The Associated Press Stylebook, MLA Handbook for Writers of Research Papers, William Strunk, Jr.’s The Elements of Style, and the US Government Printing Office Style Manual included -- leading me to believe they, too, accept such usage.

If you intend to start a sentence with a conjunction, check with your teacher first. Your teacher's opinion may be wrong, but she will be giving you a grade in any case.