This thoroughly researched article traces the life and work of Dutch-born left-wing activist, theosophist, scholar and poet Willem Siebenhaar who moved to Western Australia in 1891, and his connection with D. H. Lawrence, whom he met in 1922 and who helped him secure publication for a translation of Multatuli's Max Havelaar. Drawing on archival material such as Siebenhaar's correspondence, and on the letters of Lawrence, the article provides evidence not only of Siebenhaar's socialist (and at the time rather unpopular) ideas and attitudes, but also of the effects some of these had on Lawrence who put his acquaintance with Siebenhaar to creative use in writing his 'Australian' novel Kangaroo, particularly with regard to the fictional character Willie Struthers.