He is best known as the compiler of a book of hagiography that contains many wondrous tales of miracles in the form of dialogues between a monk and a novice, the Dialogus magnus visionum ac miraculorum, which is a consistently readable and entertaining, if somewhat sensationalistic and credulous, compilation of that lore. The work was often referred to by preachers seeking material for sermons in the Late Middle Ages. The work was popular and was widely distributed, showing that it catered well to the tastes of the times; it was perhaps the second largest late mediaeval best-seller, second only to the Golden Legend of Jacobus de Voragine. A vision reported in the book provided the source for the iconography of the Virgin of Mercy.
He is also remembered for a maxim on the rise and fall of monasteries; he wrote that discipline causes prosperity in a monastery, and prosperity undermines discipline. He also revealed the name of Titivillus as the demon who allegedly caused typographical errors in the work of scribes.
Though the priory was dissolved in 1803, when the library and archives were given to the city of Düsseldorf and the monastery and the church sold and torn down in 1809, and though at present only the ruinous apse with the ruins of the choir remains, a monument was erected in his honour near the ruins in 1897.