Your logbook is far more than just a list of dates.
No pilot is complete without a logbook. It is more than just a record of your adventures but it is a legally required document to validate your licence.
The form and layout of a log book can vary but it generally includes date, time of takeoff, time of landing, number of landings, aircraft type / registration number and conditions of flight. There is usually a separate column for the duration of the flight or time in control to make adding up for your certificate of experience easier.
The date and times of flight are essential as they will determine your experience at the end of the year to ensure that you have met the required criteria to maintain your licence. They will also be married to the aircraft log hence the need for the aircraft details. CAA examiners may require to see both and any discrepancy can lead to a shed load of trouble for both the pilot and the aircraft owner.
The conditions of flight can be weather, exercises performed, passengers carried or contributions to instrument or night ratings etc. There is generally not a great deal of room here but a few words can spark your memory tell a tale or who knows even inform a historian. Any visit to an aircraft museum will usually reveal a famous log book. Who ever knows at the time of writing when or how history will be made or indeed our part in it? I am completely confident that many routine flights have become something significant during their course and many humble pilots have gone on to great things.
It is the pilot's responsibility to ensure the accuracy of the log and that all the required criteria are met. You are also responsible for presenting your log book to a qualified person to endorse with an official stamp.
This will usually be a flight examiner or chief instructor who can certify that you have completed the required number of hours, landings etc. This is usually done on trust although you may have to produce other documents to prove yourself in certain circumstances.
It is a wise precaution to make a photocopy or scan the pages of your log book in case it is lost. You will not be the first pilot to leave your flight bag on the wing as you taxy out for take off after a careful pre flight check!
Failure to maintain proper records will result in the licence or ratings lapsing and subsequent flights being illegal. While policing of the licences and log books are pretty loose the consequences of being caught can be catastrophic and are not worth the risk.