The General pane of the preferences window (accessed from the Preferences... item in the Music Rescue menu) contains general settings for Music Rescue's operation.

Switch to Media Player when starting playback
If this option is switched on, Music Rescue will switch the Summary Panel to the Media Player pane when double-clicking a track to start playing it.
Play videos in a separate window
If this option is switched on, Music Rescue will play videos in their own window rather than in the Media Player pane of the Summary Panel. You can close this window to temporarily play the video in the Summary Panel.
iPhone/iPod touch playback size limit
Due to certain limitations in the way Music Rescue communicates with iPhone and iPod touch, an entire file has to be loaded into memory from the device before it can be changed. Obviously, this isn't desired with larger files so Music Rescue imposes a limit on the size of tracks that you can play - the limit can be adjusted with this slider.
Ignore "The" when sorting by Artist or Album
When this is switched on, artist and album names will have "The" disregarded when sorting in the track lists in Music Rescue. For example, "The Beatles" will come under 'B' rather than 'T'.