Most books on Drupal cover various aspects of developing websites using this versatile platform. After reading one of these you might find that you have done a rather good job of it and your site is attracting an increasing amount of traffic. This is great until the point where your site starts to struggle to keep up with demand. Left unchecked this could result in your site becoming slow to use and people becoming impatient and looking elsewhere. At this point you might be tempted to throw money at the problem, maybe an expensive new server or an upgrade to your hosting account. Before you do though it might be worth reading “Drupal 6 Performance Tips” by T.J. Holowaychuk and Trevor James that explains strategies and technologies that might help out.