In the first two chapters, the authors offer a short introduction to cryptographic hashing, the SHA3 competition and BLAKE. They review applications of cryptographic hashing, they describe some basic notions such as security definitions and state-of-the-art collision search methods and they present SHA1, SHA2 and the SHA3 finalists. In the chapters that follow, the authors give a complete description of the four instances BLAKE-256, BLAKE-512, BLAKE-224 and BLAKE-384; they describe applications of BLAKE, including simple hashing with or without a salt and HMAC and PBKDF2 constructions; they review implementation techniques, from portable C and Python to AVR assembly and vectorized code using SIMD CPU instructions; they describe BLAKE’s properties with respect to hardware design for implementation in ASICs or FPGAs; they explain BLAKE's design rationale in detail, from NIST’s requirements to the choice of internal parameters; they summarize the known security properties of BLAKE and describe the best attacks on reduced or modified variants; and they present BLAKE2, the successor of BLAKE, starting with motivations and also covering its performance and security aspects. The book concludes with detailed test vectors, a reference portable C implementation of BLAKE, and a list of third-party software implementations of BLAKE and BLAKE2. The book is oriented towards practice – engineering and craftsmanship – rather than theory. It is suitable for developers, engineers and security professionals engaged with BLAKE and cryptographic hashing in general and for applied cryptographyresearchers and students who need a consolidated reference and a detailed description of the design process, or guidelines on how to design a cryptographic algorithm.