If you're interested in accessing a specific PDF version, I recommend searching online or checking with your university library or local architectural organizations for availability.
Here's a brief report on the book:
Bauentwurfslehre ( Building Design Theory) Author: Ernst Neufert First published: 1936 Publisher: Various publishers, including Bauhaus Verlag and Vieweg+Teubner Language: German bauentwurfslehre neufert pdf