We undertook the writing of this book because of the lack of comparative studies of (plant) succession across biomes and disturbance types and because of the potential benefit to restoration efforts if site-specific studies were generalizable. Despite reviewing about 7,000 studies, we found only 530 of those studies useful for our detailed comparisons of various trends in succession. We used broad categories for comparison because of the large variability in site conditions, sampling methods, and documented patterns. We found some patterns that we summarize in this chapter before discussing what we see as some outstanding challenges and opportunities in successional research. Both the summarized patterns and future challenges are briefly presented in Table 17.1.