Essential Portuguese Grammar (Dover Books on Language)

Rating:
Summary: Gives you a solid foundation but not an easy read
Review: While "Essential Portuguese Grammar" gives learners of the language a solid review of grammar and serves as a handy "reference guide," for self-learners who are trying to grasp the language on their own, it is not well suited to beginners and is not meant to be an all-encompassing way to learn the language.

It's a great book for highly motivated self-learners or as a supplement to more substantive texts/audio books.