The presentation of the current state of knowledge regarding oral diseases is the main focus of this textbook. The first chapter on general pathology thoroughly addresses the topic of inflammation, which is particularly important for dental professionals. This is followed by chapters on tumors and tumor-like lesions of the oral mucosa, skin diseases that can also manifest similarly in the oral mucosa, as well as systemic diseases, salivary gland diseases, dental and jaw cysts, odontogenic tumors, and bone diseases. The final chapter discusses the topic of dental implants. All chapters have undergone a critical review for the second edition and have been supplemented with significant scientific findings. The published fourth edition of the WHO classification of head and neck tumors has been taken into account. Oral diseases are treated in the usual manner.