Anton Petrunin is Professor of Mathematics at Penn State.

“This is a succinct introduction to the tools one needs to understand metric geometry. It starts with the most basic definitions ... to move on to more advanced topics ... . There are exercises of various levels of difficulty with 'semisolutions' at the back of the book. For complicated solutions, the source of the solution in the literature is also mentioned.” (Victor V. Pambuccian, zbMATH 1541.54001, 2024)

• Preface.- Definitions.- Universal Spaces.- Injective Spaces.- Space of Subsets.- Space of Spaces.- Ultralimits.- Semisolutions.- Bibliography.

Anton Petrunin is Professor of Mathematics at Penn State.

“This is a succinct introduction to the tools one needs to understand metric geometry. It starts with the most basic definitions ... to move on to more advanced topics ... . There are exercises of various levels of difficulty with 'semisolutions' at the back of the book. For complicated solutions, the source of the solution in the literature is also mentioned.” (Victor V. Pambuccian, zbMATH 1541.54001, 2024)

• Preface.- Definitions.- Universal Spaces.- Injective Spaces.- Space of Subsets.- Space of Spaces.- Ultralimits.- Semisolutions.- Bibliography.