Great, I enjoyed reading this book, which plunges us into the late 19th century, when the United States is struggling to recover from a major stock market crash. Many people were vagabonds, hopping from train to train, an experience marked by both solidarity and freedom. The author Jack London's accounts are really detailed, and he talks about his own experiences, so it's all the more immersive. We learn about the techniques used, how they managed to evade the police and other stories.
At the end, there's a short essay in which Jack London explains how he sees vagrancy as the by-product of economic necessity, i.e., in his view, it's necessary for the economy of capitalist society to create what he calls "a reserve army", meaning that workers without qualifications are constantly replaceable. In other words, there will always be people who will accept the more arduous and precarious conditions imposed by employers. Jack London explains that within this "reserve army", and therefore among those who are constantly being replaced, there are some for whom it makes no sense to accept constant exploitation, to be fired, to look for work again; these are the ones who abandon themselves to travel through the practice of vagrancy.