From the end of the nineteenth century to the mid-twentieth century criminology assumed a recognizably modern shape. This did not mean that there were any striking innovations or radical breaks with what had been happening in the nineteenth century. Some criminologists continued to collect crime statistics and analyse crime so as to better manage and control the ‘crime problem’. Other criminologists actively did criminology as if it were a ‘science of causes’. Criminologists continued to absorb ideas and approaches from related social sciences like psychology and sociology. Because these social sciences entertained different ideas about what proper sociology and psychology should look like, these differences informed different approaches to doing criminology.