Two important similarities between LTM and a library

Encoding: Getting information into either system requires effort and skill. Dropping off a book at the library will not automatically get the librarian to add that book to the library's collection. Instead, you will need to bring the book to the librarian's attention and convince the librarian that the book would be a meaningful addition to the library's collection (otherwise, the book will be thrown out or sold at the library's book sale). Similarly, to get information into LTM, you have to pay attention to the information, and you will probably need to make the information meaningful or visual.
Retrieval: Getting the right information out at the right time requires organization. Whether you are talking about a library or a memory, it is hard to find one particular item among many items unless you know where to look. You only know where to look if the items are organized. When we are talking about memory, we usually mean that an item is organized if it is stored with a cue or grouped with other related items.