It's by far the best method for learning a language that I've ever run across. From the minute that you start the lesson, everything is in German (or whatever the language you're learning is). There's no learning by translation (i.e.: "hund = dog"), it's all total immersion.
I took three years of Spanish in highschool and always found myself very slow when trying to speak in Spanish, because first I had to think of what I wanted to say, then translate it bit by bit in my head, and then say the finished product. With TRS, when I want to say something in German, that "translate" logic isn't
there in my brain, I can just say the German.
It goes over quite a lot of the language, everything from car parts, street directions, food, hotels, standard conversations, to counting. Pretty much everything you'd need to at least get along in the foreign language while you learn all of the local idioms and specialized vocabulary that you may need.
Just as a view of what it looks like, here's a
screenshot of the listing of lessons from Unit 1 of German.