China's grip on Tibet from the visitor's point of view appears in the form of a complex set of permits.  In case you're planning  a visit, this is what you'll need.  Besides a valid Chinese visa, entry to Tibet requires the Tibetan Travel Permit which is only available to tour groups.  To get round this an imaginary group can be formed with a travel agent who then applies for the permit on behalf of the group.  The group all get on the same plane but need not know who the other members are.  However, on arrival each of the group members is in possession of a group permit so if they try to make new plans it may be questioned as to why they have left the original group.  This does not matter in Lhasa but it is best not to mention the group permit if travelling outside Lhasa when not in the original group.  Instead, one becomes an 'independent traveller' - a particular annoyance to the Chinese authorities.  Such people are 'looked after' by the FIT or Foreign Independent Traveller department.  This is essentially an overpriced monopoly travel agent.  They can approve your plans to travel in the areas requiring Alien Travel Permits and arrange these through the Public Security Bureau.  They also arrange package tours.  If you decide not to take their tours, and are not part of a group - which seems to be less than 3 people - then the permits cost 3 times more.  So, once in possession of the Alien permit you can set off provided the vehicle you use has a permit to carry foreigners, which the vast majority do not.  After searching around for a vehicle with the right permit, chances are you will end up back at the FIT in one guise or another who will make the necessary overpriced arrangements.  So much for being independent.