The Gilded Age in United States history is the late 19th century, from the 1870s to about 1900. The term for this period was derived from writer Mark Twain’s and Charles Dudley Warner’s 1873 novel The Gilded Age: A Tale of Today, which satirized an era of serious social problems masked by a thin gold gilding. The Gilded Age had its beginning in the years after the American Civil War and was followed in the 1890s by the Progressive Era. Although it was an era of rapid economic growth and prosperity, it was also a time of abject poverty and inequality as millions of immigrants—many from impoverished regions—poured into the United States, and the high concentration of wealth became more visible and contentious.