He is also oblivious to what is happening in his own household. His wife Leonie is a captivating but self-centred sybarite, whose lovers include Van Oudijck's son by an earlier wife and a Eurasian youth with whom her step-daughter is infatuated. The tensions this produces steadily mount, to be brought to a head by the haunting of the house, which drives everyone except the stalwart commissioner away.
The other main character is Eva, the wife of the residency's secretary. She has no direct involvement in Van Oudijck's domestic dramas, but offers an outsider's perspective on those, and a different perspective on the challenges facing the Dutch in Java. She organises the residency's social life (Leonie abjuring her duties in that regard), attempting to maintain European culture by putting on theatrical and musical events. And she too has some sensitivity to and understanding of Java and the Javanese way of life, explored in her close friendship with Van Helderen, a Dutchman who was born in Java and has never left it.
The Hidden Force has its tensions and dramas — a confrontation between Van Oudijck and a drunken Javanese prince, Leonie's encounter with spectral betel-spitting, and so forth — but it is largely driven by the struggles of the two central characters to build lives in a foreign land. This is a personal, moral challenge, but one that Couperus sets in its social and physical context.
Supernatural elements have a prominent place in The Hidden Force: as well as the haunting of the commissioner's mansion, a table taps out messages at some of Eva's evening parties and ultimately Van Oudijck's failure is attributed to "the Ineffable". This could be a problem for rationalist modern readers, but nothing too critical rests on these phenomena, which though not explicable remain largely isolated. In particular, Van Oudijck's psychological disintegration could as well be grounded in the breakup of his family as in his encounter with the inexplicable.
A fifteen page afterword by Ian Buruma places Louis Couperus and The Hidden Force in their historical context. Couperus had extensive experience of Java and of the Netherlands Indies' society and civil service, and everything from his descriptions of the small town and rural landscapes to his analysis of the colonial bureaucracy carries conviction. The "tropical sex" was controversial in the Netherlands in 1900 but is not at all explicit by modern standards. Some racial essentialism, evinced for example in ideas of mixed-race promiscuity, seems more dated now, but is not a central concern.
The Hidden Force is a compelling read for anyone curious about the Dutch in Java or more broadly about the psychology of colonialism and the conflict of cultures.