This companion text to contains 100 worked examples drawn from real clinical cases presenting to the authors’ institution. Cases are illustrated with peripheral blood and bone marrow cytology, tissue pathology and cytogenetic and molecular data, which are integrated to generate, where appropriate, a diagnosis based on the . The spectrum of clinical cases includes adult and paediatric patients, and both neoplastic and reactive disorders. The cases appear in no particular order to challenge the reader to make their own diagnosis. The reader will review May−Grünwald−Giemsa (MGG)-stained films of peripheral blood and bone marrow aspirates presented alongside flow cytometric data and haematoxylin and eosin (H&E)-stained bone marrow and other tissue biopsy sections. Immunohistochemistry is used to further clarify the tissue lineage and cell differentiation. Cytogenetic studies using metaphase preparations are used to identify translocations and chromosome gains and losses whilst interphase fluorescence hybridisation (FISH) studies and polymerase chain reaction (PCR) are used to identify gene fusions, gene rearrangements and deletions. Each case concludes with a discussion of the features that are important to making a diagnosis. The cases are also listed according to disease classification in the appendix so that the text can also be used as a reference. : is ideal for practicing haematologists and histopathologists with an interest in haematopathology, but particularly directed at trainee haematologists and scientists preparing for FRCPath and related examinations.