This issue of Rheumatic Disease Clinics of North America provides foundational and in-depth information about paraneoplastic and cancer treatment-related rheumatic disorders, in which every practicing rheumatologist should be well-versed. Topics covered include neoplasm risk in patients with rheumatic diseases; neoplasm risk of anti-rheumatic therapy; rheumatologic laboratory findings in malignancy; rheumatic manifestations of primary and metastatic bone tumors and paraneoplastic bone disease; neoplastic/paraneoplastic synovitis; neoplastic/paraneoplastic dermatitis, fasciitis, and panniculitis; neoplastic/paraneoplastic vasculitis, vasculopathy, and hypercoagulability; neoplastic/paraneoplastic myalgias and myositis; and less-common neoplastic/paraneoplastic syndromes.