Tell the client how to continue or what to do with the current resource
{
"book":{
"id":"2233",
"title":"How to grow apples",
"author":"Mr. Appleton"
},
"links":[
{
"href":"http://localhost:8080/library/book/2233/checkout",
"rel":"checkout",
"type":"GET"
},
{
"href":"http://localhost:8080/library/book/2233/reserve",
"rel":"reserve",
"type":"GET"
}
]
}