Recently posted was an English-German list of tatting terms (http://www.bellaonline.com/articles/art29867.asp). You may want to print it off and keep it handy when exploring the world of tatting books in the German language.
Frivolitäten und Knüpfarbeiten --Edith Wallach and Margarete Lang, (German) Berlin, Germany 1923, Ullstein Handarbeitsbücher 12.
Mizi Donner and Carl Schnebel"s book from 1913 is still in print. Handarbeiten wie als Grossmutters Zeit (Hand work like in Grandmother"s time) also listed as Ich Kann Handarbeiten (I Can do Handwork)---see German Tatting Patterns http://www.georgiaseitz.com/reviews/donnerschnebel.jpg
I"ve been searching for copies of these two books for decades. Tina Frauberger and her husband taught tatting to persons blinded during World War 1. The onion ring construction is often found in her designs. Handbuch der Schiffchenspitze (vol. 1 1917) and (vol. 2 1921) -- Frau Tina Frauberger (1917, 1921) German.
And don"t miss Helma Seipmann. I can"t say enough good things about the work of Helma Siepmann. I met her when publishing my fifth book of tatting patterns, "Tatting with Friends" (Book 5 of the Ribbonwinners Series.) She first published a series of 8 booklets as separate lessons in learning her technique while her first hardback edition was out of print. Then both a new book with everything in it and an English edition followed
This is the original hardback book translated into English.
And there is a manual in the style of the work of the famous German tatting designer, Helma Siepmann, by tatters whom I believe are her former students. This entire book is dedicated to free form tatting and concentrates on the formation of picture tatting composed of floral motifs. Absolutely inspirational for the tatter ready to work outside the realm of patterns. 64 pages, fantastically bright and beautiful color photographs on all but about 9 pages, in German. Kreatives Occhi--Gaby Dandliker & Antoinette Frei-Hofmann
Occhi Ruth Scharf (German)
Occhi: Neue Blätter (New Leaves) Ruth Scharf (German)
Review: http://www.georgiaseitz.com/reviews/scharf.html The works of Ruth Scharf are translations of Irish Crochet forms into tatting. The leaves are striking in any piece of lace.
Review: Several pages of instructions using modern photographs and reprints from antique books. Photographs and diagrams for all patterns. Many traditional style tatting patterns which are accompanied by suggestions for application as fashion accessories. Also sections on the split ring and on bead work. Final chapter encourages a foray into freeform tatting. (Patterns easy to follow from diagrams, knowledge of German not necessary.)