Norwegian-English Dictionary: A Pronouncing and Translating Dictionary of Modern Norwegian (Bokmål and Nynorsk) with a Historical and Grammatical Introduction
For more than forty years, the Haugen Norwegian–English Dictionary has been regarded as the foremost resource for both learners and professionals using English and Norwegian. With more than 60,000 entries, it is esteemed for its breadth, its copious grammatical detail, and its rich idiomatic examples. In his introduction, Einar Haugen, a revered scholar and teacher of Norwegian to English speakers, provides a concise overview of the history of the language, presents the pronunciation of contemporary Norwegian, and introduces basic grammatical structures, including the inflection of nouns and adjectives and the declension of verbs.
Okay, it's not like I was reading this one cover to cover, but I've been doing a lot of translating lately and this is, by far, the best Norwegian-English dictionary out there. Bar none.
Written by the late, great Einar Haugen - perhaps one of the best bilingual dictionaries ever written. I've used a copy for the last 20 years first as a student and then as a translator.
It has almost everything you could want to know about Norwegian - read the book description at the top of this page. The only thing it needs is an equally gifted lexicographer to update it.
This book is a fantastic resource for the incredibly cumbersome task of translating Nynorsk to English. I just wish it didn't have so many entries that just refer you to other entries--otherwise this book would've gotten a 5. For Nynorsk translation, this book has no equal.