Prehistory (Greek words προ = before and ιστορία = history) is the period of human history prior to the advent of writing (which marks the beginning of recorded history).
Prehistory, more precisely, is the period from which no known written records (including later copies) have been preserved. When did prehistory begin? People disagree. If human prehistory is defined, as presumably it should be, as the pre-literate history of Homo sapiens then at least the matter can be resolved in principle. The recent pace of progress in understanding the evolution of Homo sapiens suggests in the range of 100,000 to 200,000 years ago. Some would begin it with the first known tools, c. 2.5 million years ago at Olduvai Gorge. The first Homo erectus, around 1.5 million years ago is another possibility. Others would begin it around 40,000 BC, with the Cro-Magnons.
The end of prehistory varies according to location in the world. In Egypt, it is generally accepted that prehistory would end around 3500 BC. In New Guinea, it is generally accepted that prehistory would end around 1900. Still earlier periods of time are usually known as geological history.
Since there are no written records of this time, much of the information we know about prehistory today is contributed by archaeologists and anthropologists who study skeletons and artifacts to determine what may have happened.
Prehistory is often subdivided by a three-age system. This system of classifying human prehistory creates three consecutive time periods, named for their respective predominant tool-making technologies. It should be noted that 'stone age' people were no more trying to become 'iron age' people than we are trying to become 'plastic age' people.
The Stone Age is the time period during which humans created tools from stone. Wood, bone and other materials were also used, but stone (in particular flint) was more durable and was increasingly easily shaped for use as cutting tools and weapons. The date range of this period is ambiguous, disputed, and variable according to the region in question. It includes:
Paleolithic – Old Stone Age. This period is the oldest part of the stone age, dating from the first use of stone tools by hominids (maybe 2,000,000 years ago) to the end of the Pleistocene epoch.
Epipalaeolithic – characterised by the use of microliths, not distinguished by all scholars. It is the last period of the Palaeolithic according to some of the classification schemes used in archaeology.
Mesolithic – Middle Stone Age. It began at the end of the Pleistocene epoch around 10,000 years ago and ended with the introduction of farming, the date of which varied in each geographical region.
Neolithic – Late Stone Age, usually referring to the beginnings of agriculture. It is traditionally the last part of the stone age. It followed Pleistocene epipalaeolithic and early Holocene Mesolithic cultures with the start of farming and ended when metal tools came into widespread use in the Copper Age
Chalcolithic or Eneolithic (also "the Copper Age") – mixed stone and metal tools, not a period distinguished by all scholars. It is a phase in the development of human culture in which the use of early metal tools appeared alongside the use of stone tools.
The Bronze Age began with the use of copper and bronze tools. It was a period in a civilization's development when the most advanced metalworkers developed the techniques of smelting copper from natural outcroppings and creating alloys such as bronze, which was much harder than any other metal naturally found at that time.
The Iron Age is the period in a civilisation's development at which time iron working was the most sophisticated form of metalworking achieved. It began around 1203 BC in Turkey and the Caucasus Mountains. It came later to other areas. It didn't come to Polynesia until the coming of the Europeans, between 1500 and 1750 CE. The end of the Iron age is normally defined by the appearance of written records.