Pranciškus Baltrus Šivickis was born on 30 September 1882 into a family of small farmers in Žalakiškiai village, Šiluva rural district, Raseiniai county. He finished a three-year school in Šiluva with instruction in Russian in two years, 1898–1900. As the ban on the Lithuanian press was still in force, he learned to read in Lithuanian from prayer books and books supplied by book-smugglers. He was personally involved in the distribution of Lithuanian books and openly supported the resolutions of the Great Seimas of Vilnius. In February 1906, he left for the USA where he lived in Chicago and worked as a labourer to establish his status. From 1908 to 1911, he studied at Valparaiso University and graduated with a bachelor’s degree in natural sciences. Later he continued his studies of biology and medicine at various American universities and was an active member in the activities of Lithuanian émigrés. In 1909, he became a member of the Lithuanian Scientific Society and was editor-in-chief of the Catholic weekly Draugas (A Friend). In 1920, Pranciškus received a letter from the University of Chicago, to the effect that he was accepted for doctoral studies and was granted a stipend. A couple of years later, he defended his thesis ‘Studies on the physiology of reconstitution in “Planaria lata”, with a description of the species’ and obtained a doctorate in zoology from the University of Chicago. He combined his doctoral studies with the job of a research assistant and was in charge of laboratory practice of younger students. As he did not have American citizenship, he could not teach after his doctoral studies. In September 1922, he took a post as professor of zoology at the University of the Philippines in Manila. In 1923, he founded Puerto Galera Station of Marine Biology in the Philippines and headed it for a short time. From 1924 to 1928 he was the chair of the Zoology Department at the University of the Philippines; he taught comparative anatomy, embryology, primary zoology, and experimental zoology. Early in September 1929, the council of the university approved the professor’s resignation. He returned to Lithuania and took a post at the University of Lithuania in Kaunas. From 1 September 1940, he was confirmed a full professor at the Faculty of Mathematics and Natural Sciences of Vilnius University. On 21 July 1945, Pranciškus Šivickis was conferred the title of a merited figure of science ‘for his research and pedagogical activities in the field of biology and for extremely valuable studies into the fresh-water fauna of the Lithuanian SSR’ by the Presidium of the Supreme Council of the Lithuanian SSR. In 1947, Šivickis received the approval of his doctoral degree and professorship at the Department of Histology and Embryology, which he chaired from 1944. Presumably that was why the dean of the Medical Faculty wrote his official reference in which he emphasised the professor’s considerable scientific and pedagogical significance yet observed that he was not active in ‘public life’. The rector, who signed the recommendation, added that there were no complaints regarding Šivickis’s political orientation. On 23 September 1948, Svetlov, vice-minister of higher education of the USSR, signed the document of professor’s dismissal from Vilnius University. He was dismissed because ‘he did not ensure education of students in the leading spirit of Michurin’s biology’. On the following day, an identical document with an additional instruction to pay the salary for unused holiday was signed by the rector of Vilnius University. The resolution entered into force without delay. This was the price the outstanding scientist, whose research achievements were internationally recognised, had to pay for his opposition to the ideologisation of science and for forecasting the perspectives in the science of genetics. Having lost his job at the university, from 1948 to 1952 he worked as a senior research fellow at the Baisogala animal husbandry research station of the Institute of Agriculture, which was subordinate to the Lithuanian Academy of Sciences. Later he founded the parasitology laboratory at the Institute of Animal Husbandry and Veterinary and headed it from 1952 to 1956. He also headed the Zoology Sector at the Institute of Biology (1956–1959), the Institute of Zoology and Parasitology (1959–1960), and the Sector of Invertebrate Zoology (1960–1968). Pranciškus Baltrus Šivickis is a recognised initiator of hydrobiology, veterinary parasitology, malacology, and soil zoology in Lithuania. His name was conferred to the Helminthology Laboratory of the Institute of Ecology and to one of the lecture theatres at the Medical Faculty of Vilnius University. The Lithuanian Academy of Sciences established the P. B. Šivickis Prize, and one of the streets of Vilnius was named after him. Lithuanian and foreign researchers named several species of invertebrates after him.