[1.9] Custom Book

I believe this is the correct way to create a custom book without creating a new GUI, however the line

bookPages.appendTag(new NBTTagString("hello hi"));

will only add the string "hello" to the book and not the second half of the string. This is the same with the second page. Is there anyway to fix this? Also I'm guessing this is a terrible way of creating a custom book especially one with dynamic content, so if there are any better ways could somebody please explain! Thank you!

Code:

            	ItemStack book = new ItemStack(Items.written_book);
            	NBTTagList bookPages = new NBTTagList();
            	bookPages.appendTag(new NBTTagString("hello hi"));
            	bookPages.appendTag(new NBTTagString("page 2"));
            	book.setTagInfo("pages", bookPages);
            	book.setTagInfo("author", new NBTTagString("author"));
            	book.setTagInfo("title", new NBTTagString("title"));
            	playerIn.inventory.addItemStackToInventory(book);