This chapter describes the different types of licences and the various methods of their creation. It aims to understand the effect of licences in land on third parties. The chapter explains how a licence can be revoked. The law recognises four different types of licence: bare licences, licences coupled with a grant or interest, contractual licences and estoppel licences. In all but bare licences there is a separate component to the right which may make it enforceable against the licensor even after the licence has been withdrawn. A bare licence is purely personal to licensee and will not be binding on a purchaser from the licensor, even where he has notice of the licence. An estoppel licence is capable of registration in registered land. An estoppel licence is subject to the doctrine of notice in unregistered land. As the creation of licences is usually fairly informal so the revocation of a licence does not generally have to follow strict formalities.