A topic is defined as a seminal event or activity along with all directly related events and activities. It is represented by a chronological sequence of documents published by different authors on the Internet. In this study, we define a task called topic anatomy, which summarizes and associates the core parts of a topic temporally so that readers can understand the content easily. The proposed topic anatomy model, called TSCAN, derives the major themes of a topic from the eigenvectors of a temporal block association matrix. Then, the significant events of the themes and their summaries are extracted by examining the constitution of the eigenvectors. Finally, the extracted events are associated through their temporal closeness and context similarity to form an evolution graph of the topic. Experiments based on the official TDT4 corpus demonstrate that the generated temporal summaries present the storylines of topics in a comprehensible form. Moreover, in terms of content coverage, coherence, and consistency, the summaries are superior to those derived by existing summarization methods based on human-composed reference summaries.