I read somewhere that the Hebrew writing system evolved from Egyptian pictographs. If that's the case, have anyone read about records that trace exact evolution from a pictograph to a Hebrew letter, or is this something very hard to research because of the lack of historical data?
Wikipedia has a chart showing the Hebrew (and other) alphabets and the theorized relation to Egyptian hieroglyphs.
Evidently the Proto-sinaitic script is conjectured to be intermediate between the hieroglyphs and later true alphabets, basing most of its letterforms off of equivalent hieroglyphs according to acrophony. But it's not clear to me that this link between the hieroglyphs and the Proto-sinaitic script is well-established.