This book gives a detailed report of twenty years of scientific research, investigations and studies on the site with Middle Pleistocene fossil footprints, known as “Devil's Trails" paleontological site, which is located on the north-eastern slopes of the Roccamonfina volcano, in the locality of Foresta (municipality of Tora e Piccilli, Central-Southern Italy). The fossilised human and animal footprints, radiometrically dated to 349 3 ka years ago, are described here in detail and contextualised in the worldwide ichnological panorama. In addition to the images, a dimensional dataset is also provided of all the human footprints detected and studied and of the world’s oldest prehistoric pathway so far, from which most of the footprints branch out coordinating themselves into trackways. The report is enriched with some methodological observations that provide a state of the art of human ichnological research. Finally, historical-archaeological and anthropological-cultural evidence is also considered and discussed so providing a complete and detailed picture of one of the oldest and most important human ichnosites in the world and its territorial surroundings.