A and B cannot bind C.3 That is another way of  describing the fact that rights arising under the law of  contract alone are in personam.The  other  possibility  is  that  your  right  can  affect—bind—John.  If   your  right  is  of   this  kind,  and  the  conditions  for  John  being  affected  are  indeed  satisfied, your remedy is no longer against me alone: you can enforce the right against John. Just because your right is effective against John does not neces-sarily  mean  that  you  will  be  able  to  maintain  it  in  specie,  ie  insist  on  living  in the house: your remedy might still take the form of  money compensation for not being able to live in it, though this time against John rather than me. However, effectiveness against John is certainly a precondition for your being able  to  claim  in  specie  protection,  and  commonly  this  will  indeed  be  forth-coming. If  the law treats your right as having the potential to affect John in this way, your right is called a ‘right in rem’.4Your right to live in the house might be of  either kind. To know which, we need further information. For example, if  you simply rent the house from me, your right will be a ‘lease’, and in rem; but if  your right is to live in it with me,  as  my  lodger,  it  will  be  a  ‘licence’,  and  in  personam.  There  are  various  other possibilities, some of  each type. We shall review many, though not all, of  them in the course of  this book.