Ralf Hinze is Professor of Software Engineering at the University of Kaiserslautern–Landau (RPTU). His research is centered around the construction of provably correct software, with a particular emphasis on functional programming, algebra of programming, applied category theory, and persistent data structures. His goal is to develop theory, languages, and tools that simplify the construction of reliable software systems. Dan Marsden is a theoretical computer scientist currently working as Transitional Assistant Professor at the University of Nottingham. He is interested in the foundations of computer science, logic, and mathematics, with particular emphasis on the application of category theory.

'String diagrams have proven an indispensable tool in modern category theory, enabling intuitive graphical reasoning while doing away with much of the bookkeeping that tends to bog down equational arguments. This textbook introduces category theory by way of string diagrams, making it an excellent choice both for beginners in category theory, as well as for more experienced category theorists seeking to add string diagrammatic reasoning to their repertoire.' Robin Kaarsgaard, University of Edinburgh

• Prologue; 1. Category theory; 2. String diagrams; 3. Monads; 4. Adjunctions; 5. Putting it all together; Epilogue; Appendix. Notation; References; Index.

Ralf Hinze is Professor of Software Engineering at the University of Kaiserslautern–Landau (RPTU). His research is centered around the construction of provably correct software, with a particular emphasis on functional programming, algebra of programming, applied category theory, and persistent data structures. His goal is to develop theory, languages, and tools that simplify the construction of reliable software systems. Dan Marsden is a theoretical computer scientist currently working as Transitional Assistant Professor at the University of Nottingham. He is interested in the foundations of computer science, logic, and mathematics, with particular emphasis on the application of category theory.

'String diagrams have proven an indispensable tool in modern category theory, enabling intuitive graphical reasoning while doing away with much of the bookkeeping that tends to bog down equational arguments. This textbook introduces category theory by way of string diagrams, making it an excellent choice both for beginners in category theory, as well as for more experienced category theorists seeking to add string diagrammatic reasoning to their repertoire.' Robin Kaarsgaard, University of Edinburgh

• Prologue; 1. Category theory; 2. String diagrams; 3. Monads; 4. Adjunctions; 5. Putting it all together; Epilogue; Appendix. Notation; References; Index.

Ralf Hinze is Professor of Software Engineering at the University of Kaiserslautern–Landau (RPTU). His research is centered around the construction of provably correct software, with a particular emphasis on functional programming, algebra of programming, applied category theory, and persistent data structures. His goal is to develop theory, languages, and tools that simplify the construction of reliable software systems. Dan Marsden is a theoretical computer scientist currently working as Transitional Assistant Professor at the University of Nottingham. He is interested in the foundations of computer science, logic, and mathematics, with particular emphasis on the application of category theory.

'String diagrams have proven an indispensable tool in modern category theory, enabling intuitive graphical reasoning while doing away with much of the bookkeeping that tends to bog down equational arguments. This textbook introduces category theory by way of string diagrams, making it an excellent choice both for beginners in category theory, as well as for more experienced category theorists seeking to add string diagrammatic reasoning to their repertoire.' Robin Kaarsgaard, University of Edinburgh

• Prologue; 1. Category theory; 2. String diagrams; 3. Monads; 4. Adjunctions; 5. Putting it all together; Epilogue; Appendix. Notation; References; Index.