Unless the device is being backed up to iCloud, iTunes will automatically create a backup of your device's data each time you sync with iTunes on your computer.
You can also manually make a backup of your iOS device in iTunes. Please see this Apple article on How To Backup through iTunes
If necessary, your device can be restored from one of these backups.
Note: iTunes only keeps the most recent automatic backup of your device, so please do not sync with iTunes if you are concerned about the logbook data on your device.