Early in his career van Lennep found his natural genre, the historical novel, and his first such work, De pleegzoon (1833; The Adopted Son), was set in the 17th century. Like many of his later works it contains a strong element of adventure and a complicated plot. De lotgevallen van Ferdinand Huyck (1840; The Count of Talavera) is a tale of great charm and ingenuity told with humour and realism. Although he was the most popular Dutch writer of his time, van Lennep was weak in characterization, and few of his works appeal to the modern reader. His five-volume De lotgevallen van Klaasje Zevenster (1865; “The Adventures of Klaasje Zevenster”) was a failed attempt to write a modern novel on the French model.