[From the Editor]

Feedback is an important concept in engineering, medicine, and physiology. Positive feedback in control systems and electronic circuits can either enhance their operation or lead to instabilities, while negative feedback stabilizes and often broadens the response of the system. Similar things can happen in various physiologic systems, and feedback is an important concept from the organism to the cellular level. So what about publishing? Perhaps, in that case, positive feedback is reassuring and something I am always happy to receive, but negative feedback is also important as well. We need to know what works and what doesn´t.