Linear A is a writing system that was used by the Minoans (Cretans) from 1800 to 1450 BCE to write the hypothesized Minoan language. Linear A was the primary script used in palace and religious writings of the Minoan civilization. It was discovered by archaeologist Sir Arthur Evans. It was succeeded by Linear B, which was used by the Mycenaeans to write an early form of Greek. No texts in Linear A have been deciphered though many attempts have been made.
The term linear refers to the fact that the script was written by using a stylus to cut lines into a tablet of clay, as opposed to cuneiform, which was written by using a stylus to press wedges into the clay. Linear A belongs to a group of scripts that evolved independently of the Egyptian and Mesopotamian systems. During the second millennium BCE, there were four major branches: Linear A, Linear B, Cypro-Minoan, and Cretan hieroglyphic. In the 1950s, Linear B was deciphered as Mycenaean Greek.
Linear B shares many symbols with Linear A, and they may notate similar syllabic values. But neither those nor any other proposed readings lead to a language that scholars can read. The only part of the script that can be read with any certainty is the signs for numbers—which are, however, only known as numerical values; the words for those numbers remain unknown.
Ink-witten inscriptions in Linear A inside Minoan cup
Sir Arthur Evans: Scripta Minoa: The Written Documents of Minoan Crete. With Special Reference to the Archives of Knossos. Vol. 1, Oxford 1909
Minoan inscriptions on fired clay in Linear A script
from Phaistos, 1850-1450 BC