I just thought Id share these books with everyone, they largely focus on grammar issues so i think the level is about beginner to intermediate for learners. I think the basic requirements to know when using these is the arabic script and pronounciation, unfortunately i dont have any books specifically on those but i will post if i come across anything useful. Theres 3 books i have, ill post them in order of difficulty.
Easy Arabic Grammar:
this one focuses on the basic issues of grammar, theres lots of things to pick up from it.
Arabic Verbs and essential grammar:
this is by the same author is the first book, it focuses a lot on word structure and puts the sentence structure in the second half.
A new arabic grammar of the written language:
this is a really big book. The quality is a little poor (scanned), however if you read the other 2 books (above) first you should have too much problem recognising the arabic with markings.