"E" means "and" in Spanish ONLY when preceding a word beginning with an "i" or "i" sound as in " Pablo e Irene". It's similar to the "a" and "an" type rule in English.
Spanish also has a similar rule for "O", meaning "or".
"O" becomes "U" before words beginning with "O" as in "Pablo u Oscar" (Pablo OR Oscar).
Note that the rule is a SOUND rule so it would also apply with the silent H as in "Padre e hijo" or "Man~ana u hoy".
I think that's the whole picture.
From Dr D:
"e" is used in Spanish to conjugate or link two words when the 2nd word begins either with the letter "i" or the sound "EEE" (that's the sound of long E in English).
Ex: Espanol e Ingles son idiomas suaves.
Mira al padre e hijo.
By the way, this same thing happens with the exchange of the disjunction "or" which usually is the letter "o" but when the following word begins either with the letter "o" or the sound "O" (long O sound that is) then the letter "u" is used in its place.
