"Why is it really that architects wear black?" was a question put to Cordula Rau by an automotive industry manager during an architectural competition. Even though she herself is an architect, and wears black, she did not have an answer on the spot. So she decided to ask other architects, as well as artists and designers. She has been collecting their handwritten replies in a notebook since 2001.

In 2008, this collection of autographs appeared as a small publication ? obviously bound in black. For the purpose of the new edition, this legendary collection was expanded by new notable, amusing, pragmatic, and quirky reasons: "Please read ? and don't ask me why architects wear black!". (Cordula Rau)