Prista's book, though ok, is NOWHERE near as thorough as this one. This small book, by Sue Tyson-Ward, covers just about every section of portuguese you will need to be a fully functional speaker and I credit what I've learned to this book. I speak Portuguese with native speakers who correct me when necessary and I can say that they don't do that so often.
I see Prista's book as something for someone who is in a massive rush and who will not grasp the necessary intricacies of the language because the explanations are chopped short for the sake of saying SEE, WE TOLD YOU IT WOULD BE SHORT!
I confidently recommend the book on this page for those who need thorough explanations backed with examples. Prista's book has some pros - for example clever ways to remember Port words by learning english suffix equivalencies, etc., but at the end of the day you will walk away from the Tyson-Ward book with the capability to to read and speak Portuguese on a high conversational and literary level.