Swedish publisher and an early Esperantist (1872-1960) who, with his wife Nina Borovko-Langlet, in Budapest, is credited with saving many Jews from the Holocaust, by providing Swedish documents saying that people were waiting for Swedish nationality. Raoul Wallenberg was inspired by Langlet and used the same method to save Jewish people when he came to Budapest. Amazing World War II-dated ‘Protection Letter’ or ‘Schutz Pass’ passport booklet produced by the Swedish Red Cross and signed by Valdemar Langlet. The cloth-bound hardcover passport, 4.25 x 6, eight pages, numbered “KM 107/944,” was issued to Arpad Rotter and his wife Ilona of Budapest on August 8, 1944. The document, with text in both Hungarian and German, reads, in part: “We confirm that Arpad Rotter and his wife have Swedish interests. We draw the attention of the six-members that the above-named is under the protection of the Swedish Red Cross.” Signed at the conclusion in fountain pen by Langlet. The second page features two side-by-side photographs of the Rotters, which have been stamped and embossed by the Red Cross. The fourth page also features the couple’s personal information such as birthdates, residency, height, and hair and eye color. The protection letter expires on April 8, 1945. In fine condition, with wear to the covers and splitting to the spine, not affecting the interior pages.