Mesoamerica, along with Mesopotamia and China, is among the three known places in the world where writing has developed independently. Mesoamerican scripts deciphered to date are a combination of logographic and syllabic values. They are often called hieroglyphs due to the iconic shapes of many of the glyphs, a pattern superficially similar to Egyptian hieroglyphs. Five or six scripts have been documented in Mesoamerica, but the limits of archaeological dating methods make it difficult to establish which was earliest and hence the forebearer from which the others developed. The best documented and deciphered Mesoamerican writing system, and the most widely known, is the classic Maya script. An extensive Mesoamerican literature has been conserved partly in indigenous scripts and partly in the postconquest transcriptions in the Latin script.
Early Olmec ceramics show representations of something that may be codices, suggesting that amatl bark codices, and by extension well-developed writing, existed in Olmec times. It was also long thought that many of the glyphs present on Olmec monumental sculpture, such as those on the so-called "Ambassador Monument" (La Venta Monument 13), represented an early Olmec script. This suspicion was reinforced in 2002 by the announcement of the discovery of similar glyphs at San Andres.
In September 2006, a report published in Science magazine announced the discovery of the Cascajal block, a writing-tablet-sized block of serpentine with 62 characters unlike any yet seen in Mesoamerica. This block was discovered by locals in the Olmec heartland and was dated by the archaeologists to approximately 900 BCE based on other debris. If the authenticity and date can be verified, this will prove to be the earliest writing yet found in Mesoamerica.