You've already seen the float property used to float images so that the text wraps around them, but float can also be used to float text as well. If an element is floated, it will move to the left or right edge of its parent element (its "containing block") until it encounters the margin, padding, or border of another block-level element (floated elements automatically become block-level elements). Float has two possible values (along with the default none): left and right. An element with the property float:left will move to the left edge of its containing block, while an element with float:right will move to the right edge. You should always declare a width with a floated element; otherwise the results may be unpredictable.

You can also float both columns in a two-column layout. As Dan Cederholm points out, doing this has the advantage of placing the content column first in the HTML, which means it will be read first by screen readers and text browsers, and in older browsers that don't support CSS. However, the total width of the two columns, along with any padding and margins, must be less than 100% so that the columns float side by side.