On the alphabet: although I personally am more interested in the אלף-בית ('aleph-bet) than the אלפאבית (alphabet), several of the Hebrew letters are connected with individual letters of the Roman alphabet (e.g., I, J, and Y are all connected with 'Yod.') So it will be A-Z.
To begin with, as far as we can tell the ancestor of the letter א/A was something that looked roughly like the following:
Found in the so-called Proto-Sinaitic inscriptions, this symbol functioned as the consonant א in very early alphabetic writings. From there we move north to Canaan, where the letter was written in some manner of the following form:
It should be apparent that the second one is a simplified line drawing form of the former. In either case, the name 'aleph was quite appropriate, as the Semitic/ Hebrew root "'-l-ph" meant, in fact, an ox. In the Torah this form is rare, as it is more archaic, and is used in Deut. 28:4, as an example (שגר אלפיך).
In any event, this alphabet was in use in Canaan and through trade with Phoenicians (probably living in what is today Lebanon), the alphabet was acquired by Hellenes (Greeks). Initially they wrote without regard to direction, sometimes from right-to-left as in Semitic languages, sometimes from left-to-right and sometimes in both directions in the same document (which is called boustrophedon writing). Eventually the left-to-right writing prevailed, and with it came cosmetic changes to the alphabet. By simply taking a casual look at one representative of the early Semitic script one can see that it is well-suited for writing from right-to-left:
When the order reversed, so did the direction of many of the letters. So the 'aleph changed direction and came to look more like this:
In time and with subsequent modifications and inheritances (from the Greeks to the Etruscans to the Romans) we came to its present form: A
Although this post is titled "A" and not א I absolutely cannot resist showing some subsequent development of this particular letter:
The earlier three are early Phoenician and Hebrew 'alephs. The latter four are strictly developments in Aramaic, the second from right is Palmyrene Aramaic and the one all the way to the right was from Nabatean Aramaic.
This is a medieval 'aleph fairly typical of the massoretic codices. This one is from the Aleppo Codex (ca. 915 CE):
Obviously there is a great, great deal I left out in this exploration (including the cursive and Rashi scripts and my leaving the letter A to its development approximately 2000 years ago).
Future posts (B-Z) will hopefully be better, and will include traditional Jewish thought on the letters. :)