I read the book depicted above last summer. It was a real eye-opener. The Slate article linked below gives a better taste than any review I could write. Here’s the opening of the article, as an excerpt:
In America at the dawn of the 20th century, 25,000 little boys spent 10 hours a day in the living hell known as a coal mine. Charged with pulling detritus out of coal shipments, boys as young as 8 hunched over an ever-flowing stream of minerals, plunging in their hands to pull out slate and other rubbish. Many lost fingers or had limbs torn off by faulty machinery. Some fell down coal chutes and were smothered to death. Most, later in life, experienced horrific medical conditions like black lung. For this work, they were paid 40 cents a day.