The categories in the black bars organize the materials in groups that progress in sophistication and complexity. The resources in Entering the Conversation and Using Source Material Purposefully are relatively short, easy to use, and seek to initiate students into source-based arguments. Advancing Arguments with Evidence and Researching Self-Selected Topics depend on students already having experienced some of the the resources in the previous categories and are ready to tackle more sophisticated skills. The resources in Supplementary Resources can be used to supplement any part of the instruction.