Fungi play a major role in the function and dynamics of terrestrial ecosystems, directly influencing the structure of plant, animal, and bacterial communities through interactions that span the mutualism-parasitism continuum. Only with the advent of deoxyribonucleic acid (DNA)-based molecular techniques, however, have researchers been able to look closely at the ecological forces that structure fungal communities. The recent explosion of molecular studies has greatly advanced our understanding of fungal diversity, niche partitioning, competition, spatial variability, and functional traits. Because of fungi's unique biology, fungal ecology is a hybrid beast that straddles the macroscopic and microscopic worlds. While the dual nature of this field presents many challenges, it also makes fungi excellent organisms for testing extant ecological theories, and it provides opportunities for new and unanticipated research. Many questions remain unanswered, but continuing advances in molecular techniques and field and lab experimentation indicate that fungal ecology has a bright future.