In the previous chapter we discussed some of the major development issues to be considered when producing Web-based teaching materials. An important consideration is whether suitable materials exist already and, if so, can you use or adapt them? We have seen that one of the major strengths of the Web is the ability to use existing resources and materials by linking to them. Equally you will find on the Web a vast array of materials that you may not wish your students to access directly but are of great use to you in researching and developing your teaching materials. Either way, in order to make use of these resources you need first of all to locate them and, given the wealth of resources available, have some means of evaluating them.