diff --git a/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java b/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java
index e9dc852..c65fa4f 100644
--- a/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java
+++ b/src/main/java/org/ntlab/citrusserver/repositories/PublicBookManager.java
@@ -4,21 +4,34 @@
 import org.ntlab.citrusserver.entities.Book;
 
 import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.regex.*;
 
 public class PublicBookManager implements IBookListener{
 
     private final BookManager bookManager;
 
+    private HashSet<Book> publicBooks = new HashSet<>();
+
     public PublicBookManager(BookManager bookManager) {
         this.bookManager = bookManager;
+        this.bookManager.addListener(this);
     }
 
     public ArrayList<Book> getAllPublicBooks(){
-        return null;
+        return new ArrayList<>(this.publicBooks);
     }
 
     public ArrayList<Book> searchBooksByTitle(String title){
-        return null;
+        ArrayList<Book> books = new ArrayList<>();
+        var ptn = Pattern.compile(title);
+        for(Book book : this.publicBooks){
+            if(ptn.matcher(book.getTitle()).find()){
+                books.add(book);
+            }
+        }
+        return books;
     }
 
     public ArrayList<Book> searchBooksByTitle(String title, int sortBy){
@@ -26,7 +39,13 @@
     }
 
     public ArrayList<Book> searchBooksByAccount(String accountId){
-        return null;
+        ArrayList<Book> books = new ArrayList<>();
+        for(Book book : this.publicBooks){
+            if(book.getAccountId().equals(accountId)){
+                books.add(book);
+            }
+        }
+        return books;
     }
 
     public ArrayList<Book> searchBooksByAccount(String accountId, int sortBy){
@@ -34,13 +53,21 @@
     }
 
     public ArrayList<Book> searchBooksByTitleAndAccount(String title, String accountId){
-        return null;
+        ArrayList<Book> books = searchBooksByTitle(title);
+        for(Book book : books){
+            if(book.getAccountId().equals(accountId)){
+                books.add(book);
+            }
+        }
+        return books;
     }
 
     @Override
     public void bookChanged(Account account, Book book) {
+        if(book.getPublicity()){
+            this.publicBooks.add(book);
+        } else{
+            this.publicBooks.remove(book);
+        }
     }
-
-
-
 }