Data provenance refers to the establishment of a chain of custody for information that can describe its generation and all subsequent modifications that have led to its current state. Such information can be invaluable for a forensics investigator. The first step to being able to make use of provenance for forensics purposes is to be able to ensure that it is collected in a secure and trustworthy fashion. However, the collection process along raises several significant challenges. In this chapter, we discuss past approaches to provenance collection from application to operating system level, and promote the notion of a provenance monitor to assure the complete collection of data. We examine two instantiations of the provenance monitor concept through the Hi-Fi and Linux Provenance Module systems, discussing the details of their design and implementation to demonstrate the complexity of collecting full provenance information. We consider the security of these schemes and raise challenges that future provenance systems must address to be maximally useful for practical forensic use.