Here are some of his notable writings:
1. "De ondergrondse pers" (1948): This book is a detailed account of the underground press in the Netherlands during the German occupation. It examines the different groups involved in the production and distribution of underground newspapers and magazines, as well as the challenges they faced, such as censorship, arrests, and executions.
2. "De Duitse bezetting van Nederland: een kroniek" (1949): This book provides a chronological account of the German occupation of the Netherlands, from the invasion on May 10, 1940, to the liberation in May 1945. It covers various aspects of the occupation, including the establishment of a puppet government, the persecution of Jews and other minorities, the Resistance movement, and the devastating effects of the war on Dutch society and infrastructure.
3. "De NSB: de nationaal-socialistische beweging in Nederland" (1951): This book provides an overview of the history and activities of the National Socialist Movement in the Netherlands (NSB), which was the largest fascist party in the country before and during the Second World War. It examines the party's ideology, propaganda efforts, collaboration with the German occupiers, and the role of the NSB in the persecution and murder of Dutch citizens.
In addition to these major publications, Helmar Drost also contributed numerous articles and essays to various newspapers, journals, and magazines, mainly focusing on topics related to the Second World War, the Resistance, and Dutch society during the occupation. His writings have had a lasting impact on the study and remembrance of the war in the Netherlands and continue to be regarded as valuable sources of information and historical analysis.