Currier and Ives was a firm headed by Nathaniel Currier (1813 - 1888) and James Merritt Ives (1824 - 1895). Currier and Ives described itself as "Publishers of Cheap and Popular Pictures."
Their pictures were indeed hugely popular. From 1835 to 1907 they produced over a million prints by a process of hand-colored lithography. The colors were applied in an assembly-line style of operation by German immigrant girls, each of which added a single color to the print.
Today, original Currier and Ives prints are much sought-after by collectors, and modern reproductions of them are popular decorations.