This 1970 Belgian semi-postal set honors four prominent national figures—M. Baers, J. Cardijn, C. Huysmans, and P. Pastur—each recognized for significant contributions to Belgian public life, social development, and politics. Issued with surtaxes (additional charity values), the stamps supported social welfare initiatives, a common practice in Belgian philately. The finely engraved portrait designs reflect Belgium’s tradition of high-quality intaglio printing and minimalist typography, making the set attractive both historically and aesthetically. Complete sets are especially desirable for collectors specializing in European semi-postal issues, Belgian political history themes, or portrait definitive-style commemoratives. Well-centered mint examples with intact perforations command premium collector interest.