Code reviews are conversations about proposed changes, serving both technical and cultural purposes. They help find bugs, identify security concerns, ensure style consistency, maintain code quality, train team members, foster ownership, and provide an opportunity to learn from others. Effective code reviews require adjusting communication styles according to the intended audience and relationship with them. The goal is to build a community of developers eager to contribute, promoting a quality product. Participants must respect each other's expertise, assume good faith, and strive for clarity and friendliness in their feedback. Successful code reviews result in higher quality changes, strengthened relationships, and increased understanding among team members.