In the comprehensive description of Nomarski differential interference-contrast (DIC) microscopy, the fundamentals and experimental designs (Part I) and the formation of the interference image (Part 11) were discussed and a comparison made with the phase-contrast technique (Part 111) [26. 27. 28]. The present Part IV will now give a review of the applications of Nomarski DIC microscopy together with a list of references. No claim is made with regard to the completeness of the bibliographic data in view of the rapidly increasing number of applications and publications on the subject. The bibliography is therefore only intended to serve as a guide to the potential uses of the Nomarski DIC method in the different fields of microscopy of organic and inorganic objects.