This chapter discusses intervention with an internet sexual offender. Internet sex offenders represent a heterogeneous group of men who engage in sexual offenses against children that have a lot in common with voyeurism. While there is some understanding of which men pose the greatest risk to children in the offline environment, these do not apply to many of those convicted of Internet-only offenses. The challenge is whether they have a need for treatment at all, and if they do, whether these treatment needs can be met by existing programs and alongside other sexual offenders. The case of Mr. M highlights difficulties with emotional and sexual relationships and a reluctance to form close interpersonal bonds. The case also illustrates how the Internet affords opportunities to meet sexual and emotional needs and facilitates access to deviant material which might otherwise never have been obtained, or not without considerable effort and greater risk of detection than via the Internet with its particular features of accessibility anonymity and affordability. (PsycINFO Database Record (c) 2019 APA, all rights reserved)