I received this question:

I was wondering if students needed any other book besides the Lingua Latina book?  There appear to be a couple of other books that are part of the Lingua Latina ‘program’.

Here is my reply:

The only other piece I would recommend would be the instruction manual Mr. Ørberg wrote.  But, if you are in class, even that book is not necessary.  

Here it is if you are interested: http://www.amazon.com/Lingua-Latina-per-Illustrata-Students/dp/1585100501/ref=sr_1_8?ie=UTF8&qid=1437047337&sr=8-8&keywords=lingua+latina

Ignore the other books.  I would recommend them for Latin teachers, not students.  Lingua Latina is all you really need.