Dear Reader: It is with great pleasure that we can report that MGE now begins its fourth volume. In its first three years MGE has continued to attract high quality research articles, reviews and a lively selection of commentaries which cut across all domains of life. For this we would like to thank all of the authors who have contributed to volumes 1–3. We would also like to take this opportunity to thank the many reviewers, the Editors and also the fantastic and indispensable team at Landes Biosciences for their support and expertise which has underpinned the success of MGE. Just like the subject of the journal, the journal itself is continuing to evolve. Those of you who follow MGE will already be aware that we have moved to an online only format; a change based on usefulness rather than necessity. There will be more changes to the format of MGE occurring in 2014. With the general movement towards open access we are going to change the way we do things and we will currently provide open access free for all of our authors. Additionally we are going to move to issueless volumes from now on with content being uploaded as and when it is accepted. We plan to compile special focus topics, where a group of articles can all be grouped according to a particular theme, regardless of their publication date. We think these themes should come from our readers where articles from all volumes will be grouped under a particular heading, if you have an idea where this would be useful; e.g. cancer, Archaea, etc., then please let us know and we will arrange it on the MGE website. The aim is to make searching for articles on a particular topic more easy for our readers. Finally, if anybody has suggestions, comments or criticisms, please do not hesitate to contact us and we will be happy to engage with you and look for improvement of MGE. Adam P Roberts, Editor-in-Chief Kathryn Sauceda, Managing Editor Elaine Ellerton, Assistant Editor