The Etruscans were the first people in the Italic peninsula to learn to write. They adopted the Euboean Greek alphabet, and from them writing spread to other cultures of the Italic peninsula such as the Romans.
The Etruscan language has never been conclusively shown to be related to any other language in the world. The problem is compounded by the fact that the textual corpus is limited in scope, mostly from tombstones. Imagine trying to reconstruct any language from texts in cemetaries. Chances are you'll get geneological words, personal titles, and brief dedicatory sentences. There are some bilingual texts with Phoenician, but they are short and few in number. As a consequence, the Etruscan language remains poorly understood.
The following table represent various stages of the Etruscan alphabet. The "Model" alphabet is basically the Euboean Greek alphabet, and was not used but probably learned as part of a literate person's training. The "Archaic" alphabet was used between the 8th and 4th century BCE, before the Etruscans were part of the Roman Empire. The "Late" version was used from the 4th century BCE to the 1st century CE, at a time when Etruscan as a language was rapidly being replaced by Latin. The knowledge of Etruscan finally died out by the 1st century CE.
As the above table indicates, the source of the Etruscan alphabet is the Euboean variant of the Greek alphabet. This explains the presence of the letters F and Q, and the usage of H for the [h] sound (instead of [e:]) and X for [ks] (instead of [kh]). The adoption possibly occurred as early as the 8th century BCE, before the general standardization of the Greek alphabet, as indicated by the archaic shapes of the letters, and the and the direction of writing (which is either right-to-left or boustrophedon).
The Etruscan language did not have many of the sounds that the Greek language had. So while they did adopt nearly all letters in the Greek alphabet, they left many of them unused (such as Β, Δ, Ζ, Ο. In addition, they took Γ; and changed it to represent the [k] sound. This, in turn, means that there are now three letters that represent the [k] sound, namely C, K, and Q. The Etruscans decided to use all of them, but each one in a prescribed environment: K appears before A, C before I and E, and Q before V.
The letter F represented either the sound [w] or [v], as it is in Euboean Greek. However, Etruscan did have the sound [f]. In the early stages of the alphabet, the digraph (HF) was used to write the [f] sound. Later on, the letter 8 replaced *HF*.
The Etruscan alphabet was the foundation for many other alphabets such as Oscan, Umbrian, and maybe even Futhark. However, its descendent, the Latin alphabet, would come to be one of the most widely used alphabets in the world.