Plants are constantly under attack by pathogens, pests, and parasites, resulting in severe consequences on global food production and human health. While pathogens and pests find their ways to invade and communicate with their hosts, plants have evolved sophisticated immune systems fight infections. In the field of plant-microbial interactions, although over the past years most of the studies have focused on the function and signaling pathways of plant disease resistance (R) proteins and pattern recognition receptors (PRR), as well as pathogen effector proteins, many new important research areas have emerged. This Special Issue includes eight invited review articles and four research papers. These reviews highlight the recent advances and latest discoveries in these new research areas and also touch on current serious issues in the crop production industry, aiming to attract more attention to these important, but often overlooked areas, and to stimulate new ideas for future research in the field of plant-biotic interactions.