Architects' Data (German: Bauentwurfslehre), also simply known as the Neufert, is a reference book for spatial requirements in building design and site planning.

First published in 1936 by Ernst Neufert,[1] its 39 German editions and translations into 17 languages have sold over 500,000 copies.

Teaching at Weimar's Bauhochschule from 1926 after graduating from the Bauhaus, Ernst Neufert began to collect data about building, in a way of rationalization.

The book is conceived to help the initial design of buildings by providing extensive information about spatial requirements.

The Argentine artist Guillermo Kuitca worked on the rationalization of architecture within his piece "Neufert Suite" in 1998.