These books are great resources for those interested in crystallography. To use them, simply open the book and start reading. You can keep them on your bookshelf or take them with you to study. When handling the books, be careful not to damage them further, especially since page 71 of one book is already detached. To maintain them, keep them in a dry and cool place to prevent any further staining or damage. Avoid exposing them to direct sunlight for long periods to prevent more sunning of the spine and label. Also, try to keep your hands clean when reading to avoid adding new stains to the interior pages.