The Phoenician script is an important "trunk" in the alphabet tree, in that many modern scripts can be traced through it. Arabic, Hebrew, Latin, and Greek scripts are all descended from Phoenician.
Phoenician is a direct descendent of the Proto-Sinaitic script. Like Proto-Sinaitic, Phoenician is a "consonantal alphabet", also known as "abjad", and only contains letters representing consonants. Vowels are generally omitted in this phase of the writing system.
The major change between Proto-Sinaitic and Phoenician is graphical. The Phoenician letter shapes grew to be more abstract and linear, in comparison to the more "pictographic" shape of Proto-Sinaitic signs.
The following are the 22 Phoenician letters.
There were many branches that sprang up from Phoenician, like Hebrew, Greek, and Aramaic. Phoenician itself remained in use, in the form of Punic (more cursive), until about 200 AD.