He is an active member of the editorial board for the Czech journal Salve,[5] which deals with theological, historical, philosophical, and cultural themes.
The first topic that Petráček chose to investigate in his scholarly work was the social and economic history of the early Middle Ages in the Czech lands, focusing on the lower strata of society in particular.
One of the key figures in Fribourg was the Old Testament Exegesis Professor Vincent Zapletal (1867–1938) of the Dominican Order, who worked at the Theological Faculty of the University from 1893 to 1928.
Zapletal was among the most significant figures in progressive Catholic exegesis, along with the French biblical scholar Marie Joseph Lagrange OP and German Jesuit Franz von Hummelauer.
Zapletal sought a scientific interpretation of the Bible and employed a historical-critical method, and became a victim of the anti-modernist crisis in the Catholic Church between 1904 and 1914.
Petráček completed a critical biography entitled Bible Science in the Period of the (Anti-) Modernist Crisis: The Life and Work of Vincent Zapletal OP (1897–1938).
Roman Catholicism in Modern Czech Society and the State, author explores the various processes which culminated in Roman Catholicism drastically falling in both position and status in the modern Czech culture, society, and state, thus rendering a privileged and self-confident national church a problematic, humiliated, barely tolerated and, for much of the 20th century, brutally persecuted community.
Anthropological Concepts of the Middle Ages in a Transcultural Perspective, the author analyses how Medieval culture and civilization in Europe was able to come to terms with cultural, social and religious plurality and diversity without posing a threat to solidarity, openness, dynamism and the actual functioning of society using selected phenomena such as Inquisition, Canon Law, Cult of Relics etc.