These vintage books are great for anyone interested in learning about genetics and heredity. To use them, simply open up the pages and start reading. When handling the books, be gentle to avoid any damage to the bindings or pages. Since they're old, there might be some minor soiling and writing, but this doesn't affect the readability. To maintain them, keep them in a dry and cool place away from direct sunlight. Don't place heavy objects on them to prevent warping. If you want to clean them, use a soft, dry cloth to gently wipe the covers and spines.