Chapter Five examines the problematic nature of expertise in psychical investigation, and the equally troublesome question of whether skills in the physical sciences were relevant to and useful in such investigations.Although spiritualists, psychologists and conjurors disagreed about many other psychical-related issues, all three kinds of audience shared grave misgivings about physical scientists in sites of psychical enquiry. This chapter argues that while psychologists sought to exclude physicists from psychical enquiry because they perceived huge differences between ‘tricky’ psychical instruments and reliable instruments of physics, leading physical-psychical scientists sought to collapse this distinction: they often believed that their experience of and skills in handling ‘tricky’ instruments of physics gave them important qualities to bring to the psychical expert.