An area at the beginning of each session on a recordable compact disc which is left blank for the session's Table of Contents (track numbers and start-and-stop points) and other miscellaneous information about the disk and about the recorded tracks. The lead-in is written when a session is closed, and takes up 4500 sectors on disk (1 minute, or roughly 9 megabytes). The lead-in also indicates whether the disk is multisession and, if the disk is not closed, which is the next recordable address on the disk.