The nearest equivalent to Duden for the German language or the Chicago Style Guide for the USA used to be Hart’s Rules (first published in 1893). It was replaced by the more longwinded Oxford Style Guide. But in September 2005 the publisher decided to go back to Hart’s Rules. At amazon.de (and UK and USA) you can look inside the book.

The set of books you might use consists of New Hart’s Rules, New Oxford Spelling Dictionary (useful for word divisions) and New Oxford Dictionary for Writers and Editors. They are also sold as a set, Writer’s Reference Pack.

The recommendations in these books are those followed by Oxford University Press, rather than those followed by the majority of publications. But apart from the use of -ize instead of -ise in many words and the serial comma (both of which I like), the recommendations are fairly standard.

Another superb book is Copy-Editing, by Judith Butcher.