This lustrum edition has a number of specials. We invited two interesting and surprising keynote lecturers. We will go out to explore on sea, on board of the TX44, and visit the port of Den Helder, the Wadden Sea mudflats and the Razende Bol, the latter for seal watching. And of course we have a lustrum photo competition, so bring your camera! We thank NWO for sponsoring and we wish you interesting and fruitful NCK days 2017!