While many associate written Hebrew with the squarish letters adorned by curvy flourishes and occasionally vowel marks, Hebrew was originally written with a different, but related, script called Old Hebrew. The first evidence of this script is the Gezer Calendar, which dates to around the 10th century BCE and records agricultural activities throughout the year. This early form of Old Hebrew is graphically very similar to Phoenician. Also, like early Phoenician, Old Hebrew inscriptions did not indicate vowels (not even the simple matres lectionis system where the letters aleph, yodh and waw represented vowels in addition to consonants).
The following chart is the Old Hebrew alphabet from roughly the 8th century BCE.
During the exile to Babylon (6th century BCE), the Hebrews started to use the Aramaic language and script, using Old Hebrew mostly in the religious writing. In later periods, Old Hebrew was sometimes inscribed on coins as a tool for Hebrew nationalism. The Old Hebrew alphabet ceased to be used at all by the 1st century CE.
The Samaritan alphabet is derived from Old Hebrew.