This 20-page pdf by Walden Fonts gives a potted history of Fraktur in many of its forms, from the days of Dürer to the 20th century. This is typography rather than calligraphy if you're being picky, but it's still an interesting read - and for those who will have no truck with the printed word there's a bit about Kurrent and Sütterlin. There's a section on typesetting conventions which answered a few questions which had been nagging me, such as how do you emphasise a word within a body of Black Letter text, and when should you use a round "s" instead of a ʃ. Come to think of it, it's entirely possible that I'm the only one who finds such things interesting.
The link goes direct to the pdf, so it'll either open or download depending on your browser and how it's set up.
Five Centuries of German FrakturAlternatively you can visit
this page which has a few downloadables; the Fraktur book is "The Gutenberg Press - Manual".