This book has been dated by Ingeborg to c. 1590, although I haven't been able to find details on how this date was determined. According to Ingeborg, this book was probably used by journeyman tailors as a catalog of items they need to know how to make before they can become masters of their trade. Because of this, some of the garments may be "traditional" and someone old-fashioned for the date of the book. The peascods on some of the doublets offer a little help with the dating.
There is some interesting construction throughout: the neckholes on page 9, the large triangular sleeve cutout on page 12, and the especially interesting (to me, anyway) items on pages 25, 35, 36 and 37. The two discernable women's gowns are on pages 36 and 37. As for what's going on with their waistline, my guess is that the bodice seams were sewn together, the skirt seams sewn together, and the excess at the waistline pleated to the waist and sewn down. I've seen some German gowns that resemble this cut, albeit from the first half of the 16th century.
I have yet to decipher the handwriting; currently I can figure out about one word in four. I am looking for someone versed in 16th century German paleography and 16th centuury German costume terms to help decipher this manuscript. Even one deciphered page to use as a key would be immensely helpful. If you know anyone who might be interested in this or have some input on the content of the pages, please email me.