Sometime ago one of the peeps from my club had his flightbag stolen from his car containing headset, GPS, etc - but most important his log book. The hardware can be repleced (insurance paying for it) but the log book? A unique and only record of your flying history - and required to be updated and to be shown to the CAA when required.
So what can be done? I guess duplicate books, one safe at home, the other in your flight bag? Periodically photocopy your log book for the record?
Thoughts?