On the International Site (English) of the Personnel Department of the Faculty of Science:
click on the link Foreign Employees/Guests where a lot of information may be found on residence permits, visas, insurances and so on. Please check this carefully, as it may answer most questions you have!
The FWN Personnel Department (contact ms Nori Poppeliers, phone outside NL +31 (0)71 5274192 phone inside NL/outside Leiden: 071 5274192; phone inside Leiden 5274192; university extension 4192) sees to it that all the obligatory paperwork is done before or shortly after the arrival of new employees. It is also quite helpful in providing information and suggestions that help newcomers to function in Dutch society.
Other names to know are: