Al is the Arabic definite article meaning "the".
Often people become confused when seeing authors spell Arabic names in different ways and then wonder whether it is the same or a different person, term or concept.
Some render the name of the Muslim historian and commentator as "Al-Tabari" and others or "at-Tabari", or the different names of God can be found variously rendered as "al-Rahman", "al-Sami", "al-Shakur", "al-Nur" etc. or as "ar-Rahman", "as-Sami", "ash-Shakur", "an-Nur" etc.
In Arabic the consonantal letters of the alphabet are divided into 2 groups: lunar letters and solar letters (from Latin: luna meaning moon, sol meaning sun).
The lunar letters are pronounced clearly after the definite article "al", e.g., qamar (meaning moon) becomes al-qamar, balad (country) al-balad.
But when the word begins with a solar letter such as Sh in Shams (meaning sun), the letter "L" in the definite article "al" is not pronounced. Consequently, the word sun which is "shams" will be pronounced "ash-shams" although it is still written in the Arabic text as "al-shams".
Some of the solar letters are: D, N, S, Sh, T, Z etc.
Some of the lunar letters are: Q, K, F, M, B etc.
It is a personal preference whether authors transliterate the spelling or the pronunciation of the original Arabic in their articles.
We consider it generally more helpful to transliterate the pronunciation, because it will enable readers who do not know Arabic to pronounce correctly what they read.