For those preparing for an introductory real analysis course, several supplementary materials are recommended. Velleman's proofs book is noted as a good resource, although some participants express skepticism about its effectiveness for real analysis, suggesting it may focus more on sequences and series. The Rudin book is heavily criticized, with claims that it is outdated and not suitable for beginners, especially for those unfamiliar with proofs. Instead, "Guide to Analysis" is suggested as a potentially better alternative. Additionally, watching online lectures from Harvey Mudd College is mentioned as a helpful resource. Participants emphasize the importance of understanding the foundational concepts of real analysis rather than getting bogged down in complex texts. Overall, the discussion highlights the need for accessible materials that align with the introductory nature of the course.