A useful Portuguese reference grammar divided into 2 basic sections, the 1st section goes over basic grammar categories; nouns, articles, verbs, prepositions, etc. and the second half discusses specific social scenarios and vocabulary. This grammar also does a good job of comparing some of the nuances and differences between the Portuguese spoken in Portugal and Brazilian Portuguese, which is the version that I am more familiar with since I lived in Brazil for 3 months a few years ago and I was able to learn it fairly quickly since I had studied Spanish for 4 years in high school and I was able to use that knowledge to learn Brazilian Portuguese at an accelerated rate.
The only critique I have of the book is that they put all of the differences for Brazilian Portuguese in a separate section towards the end of the book, so you have to flip back and forth to see the differences where there is a subscripted B in the main text indicating there is a difference in Brazilian Portuguese. It would have been more convenient to place that material in footnotes rather than having a separate section for key Brazilian Portuguese grammar differences as it appears in the book. This is the second edition, so hopefully if they make a third edition they could make that change to it along with additional updated content.