void GetNames()
        {
            PersonBLL author = people[Book.AuthorID];

            FirstName = author.FirstName;
            LastName  = author.LastName;
        }
        /// <summary>
        /// Takes each book and creates a list of strings from the fields to be searched for.
        /// </summary>
        /// <param name="b"></param>
        /// <returns></returns>
        List <string> ConcatenateBookFields(BookBLL b)
        {
            List <string> concatenatedFields = new List <string>();

            concatenatedFields.Add(b.Title);

            if (b.Subject != null)
            {
                concatenatedFields.Add(b.Subject);
            }

            PersonBLL author = (from a in people
                                where a.ID == b.AuthorID
                                select a).FirstOrDefault();

            concatenatedFields.Add(author.FirstName);
            concatenatedFields.Add(author.LastName);

            return(concatenatedFields);
        }
        /// <summary>
        /// Returns a detailed summary of the book for the search result pages.
        /// </summary>
        /// <returns></returns>
        public string Details(PersonBLL p, int checkedOut)
        {
            string output = $"{Title}\n" +
                            $"By: {p.FirstName} {p.LastName}\nISBN: {ISBN}\n";

            if (NumPages != null)
            {
                output += $"{NumPages}pg\n";
            }
            if (Subject != null)
            {
                output += $"Subject: {Subject}\n";
            }
            if (Description != null)
            {
                output += $"{Description}\n";
            }
            if (Publisher != null)
            {
                output += $"Published By: {Publisher}\n";
            }
            if (YearPublished != null)
            {
                output += $"Published In: {YearPublished}\n";
            }
            if (Language != null)
            {
                output += $"{Language}\n";
            }
            int availableCopies = NumberOfCopies - checkedOut;

            if (availableCopies > 0)
            {
                output += $"Availble Copies: {availableCopies}/{NumberOfCopies}";
            }
            else
            {
                output += $"NO COPIES AVAILABLE: 0/{NumberOfCopies}";
            }
            return(output);
        }