This is a great grammar for learners of Norwegian. Everything's clearly laid out and accessible. I found the list of the most common mistakes made by English speakers and the tables of strong and irregular verbs at the back particularly useful. Norwegian grammar's not all that complicated really, so this will last you until you're getting to a fairly advanced level, and at that point you'd do well to get a Norwegian grammar in Norwegian. There are few cultures in the world as interested in their own language as the Norwegians, so there are plenty to choose from! I'd recommend Finn-Erik Vinje's "Norsk grammatikk" which is nice and user-friendly, or Kunnskapsforlaget's "Språkvett", which isn't a proper grammar really, but a very useful compendium of articles on the most commonly asked questions about grammar and correct usage.