Both Bradley F. Smith's Heinrich Himmler: A Nazi in the Making (Hoover Institution Press, 1971) and Peter Longerich's Heinrich Himmler (Oxford University Press, 2012) record that the then 20 year old student read Böhme's The Diary of a Lost Soul (an alternate title). Himmler kept a record of his reading, and notes having read Böhme's book in March 1920, while in Munich and Ingolstadt. At the time, according to Longerich, Himmler's reading was largely novels and stories "concerned with love, erotic attraction, and the battle of the sexes."
According to Smith, The Diary of a Lost Soul caused Himmler to "reexamine his attitudes" and doubt "the scorn he usually poured on those who had wandered from the path of virtue." It was a book, Himmler noted, "that offers insight into dreadful human tragedies and makes one look at many a whore with different eyes." Afterwords, he went on to read other not-unrelated books, including Henrik Ibsens's A Doll's House.
I also just recently learned that The Diary of a Lost Girl received a shout-out in The Storyteller, a 2013 novel from author Jodi Picoult. The Storyteller, a #1 New York Times bestseller, is based on an incident which took place during the Holocaust. In one scene, a key character is preparing to flee, and is gathering important possessions.
From the time it was first published in 1905, The Diary of a Lost Girl continued to sell and remained in print in various editions all the way into the early 1930's, when it was driven out of print by right wing German groups upset with its story. (Himmler read an edition published in 1917.) Along with the anti-war novel All Quiet on the Western Front and works by Thomas Mann, Böhme's The Diary of a Lost Girl was one of the dozen bestselling books in Germany in the period from 1900 to 1939. It is believed to have sold more than 1.2 million copies. The book is back in print in Germany and the United States.
Pictured here is a newly acquired edition of Böhme's bestseller. This rare softcover copy was published in 1919.