The peripheral T-cell lymphomas (PTCLs) are a heterogenous group of rare entities. Whilst cytogenetic and molecular identifiers are being identified, accurate diagnosis remains challenging, requiring careful, expert integration of the clinical and pathological findings. The treatment of PTCL is also challenging. Protocols for the different subtypes are only just beginning to emerge, hindered by the complexities of conducting trials in such uncommon and varied conditions. While first-line treatment with conventional chemotherapy is seldom curative, patients who achieve remission may be eligible for stem cell transplantation, offering the possibility of long-term disease control if not cure. Targeted biologics are also being developed as unique cytotoxic markers are identified. ‘Fast Facts: Peripheral T-Cell Lymphomas’ is a new title in the Fast Facts extensive hemato-oncology library, written by experts in this emerging field. This handbook will be useful to anyone involved in the care of patients with PTCL, including haematologists, oncologists, specialist nurses and primary care providers, raising awareness of these rare lymphomas and the current – and emerging – approaches to diagnosis and treatment.