In this small series of posts I want to have a critical look at some of the older articles and put them into the current context. For a start, I picked the review article from 2011 in Science: “Microresonator-based optical frequency combs” by T.J. Kippenberg, R. Holzwarth and S. A. Diddams. In many papers of the field it is still one of the first references for Kerr frequency combs. In other papers, which are only distantly related to Kerr frequency combs, it might be the only reference for Kerr frequency combs. However, if a reader not familiar with the field reads only this review, he or she will have a much skewed view of today’s Kerr frequency combs. The reason is mostly that the review was published only four years after the first paper on Kerr frequency combs and by now it has been another six years in which the field has moved in some respect much beyond the state of the review. I would recommend these readers to also have a look at the much more recent “News & Views” in Nature Photonics by A. Weiner, which gives a brief update on what has been happening over the last years. But let’s go back to the Science review and have a look at some details.