Prehistory generally refers to the time before writing was invented and practiced, while history typically refers to the time period after which written records still exist. However, there is no clear dividing line between the two periods.
History generally refers to events that were recorded. The Greeks wrote extensively about their culture and other cultures, and most of history after Greek times is well documented. However, the civilizations in the New World did not leave behind extensive notes, so prehistory refers to a later date for North and South America.
Experts debate whether early Egyptian culture should be considered prehistoric. While the Egyptians had a writing system, no paper documents have been discovered, so the history people have access to today is limited. Other cultures took extensive notes of Egyptian culture later, but it is unclear if their documents are reliable.
Other experts argue about when the prehistoric period ended. Most ancient writing is forever lost, and people have access to what survives primarily through translations and copies. The veracity of this information is difficult to determine, and translators and transcribers sometimes add or remove information accidentally or on purpose. Most of human history is not recorded. The only way to determine how early human civilizations functioned is by examining where they lived and what they left behind.