It's impossible to give a complete list of commercial and publicly available products in this book because new products are constantly being introduced and capabilities are constantly being added to existing products. Instead, we concentrate on discussing generic features and capabilities, and the consequences of having — or not having — particular capabilities, so that you can make your own evaluation of the products currently available to you. We do periodically mention individual products, some commercial and some publicly available, particularly when there are striking features of well-known products. This is not intended to be an endorsement of the products we mention, or a slight to products that we omit.