I have to say it's by far the best portuguese textbook I've come across so far. If you just want to learn a few words for a holiday, forget it but if you want the full, immersive experience, get this, and the workbook, and download the mp3s of the audio exercises here: http://www.linguatextltd.com/LinguaPo... and you'll be on the road to a serious grasp of the language.
The edition I have is actually Dias-Lathrop-Rosa, 1st revised addition, c. 1977 with the accompanying work book, as used by my uncle when he was in college.