This is a technical-scientific manual describing the main algorithms used for differential diagnosis in the field of haematology and biochemistry in the small animal clinic. The objective of this book is to optimize the work of clinical veterinarians by providing them with the necessary tools to guide and facilitate the diagnosis of the main haematology- and biochemistry-related diseases of small animals and to establish aetiology based on specific clinical signs. The authors, experts in the field of small animal haematology and biochemistry, include additional resources (tables, images, etc.) that make this manual an essential reference for veterinarians working with cats and dogs.