Arthur Ogus is Professor Emeritus of Mathematics at the University of California, Berkeley. His work focuses on arithmetic, algebraic, and logarithmic geometry. He is the author of 35 research publications, and has lectured extensively on logarithmic geometry in the USA, France, Italy, and Japan.

• 1. The geometry of monoids; 2. Sheaves of monoids; 3. Logarithmic schemes; 4. Differentials and smoothness; 5. Betti and de Rham cohomology.

'Logarithmic geometry is a framework tailored for studying two fundamental aspects in algebraic geometry; compactification and degeneration. It has spectacular applications to p-adic Hodge theory, ramification, etc. Written by a top researcher in the field, this book deals with the foundation of the theory. Emphasis is placed on the geometry of monoids, on which log geometry is based, and on logarithmic smoothness, a key concept of the theory. The reader will be enabled to explore the fertile field.' Takeshi Saito, University of Tokyo

Arthur Ogus is Professor Emeritus of Mathematics at the University of California, Berkeley. His work focuses on arithmetic, algebraic, and logarithmic geometry. He is the author of 35 research publications, and has lectured extensively on logarithmic geometry in the USA, France, Italy, and Japan.

• 1. The geometry of monoids; 2. Sheaves of monoids; 3. Logarithmic schemes; 4. Differentials and smoothness; 5. Betti and de Rham cohomology.

'Logarithmic geometry is a framework tailored for studying two fundamental aspects in algebraic geometry; compactification and degeneration. It has spectacular applications to p-adic Hodge theory, ramification, etc. Written by a top researcher in the field, this book deals with the foundation of the theory. Emphasis is placed on the geometry of monoids, on which log geometry is based, and on logarithmic smoothness, a key concept of the theory. The reader will be enabled to explore the fertile field.' Takeshi Saito, University of Tokyo

Arthur Ogus is Professor Emeritus of Mathematics at the University of California, Berkeley. His work focuses on arithmetic, algebraic, and logarithmic geometry. He is the author of 35 research publications, and has lectured extensively on logarithmic geometry in the USA, France, Italy, and Japan.

• 1. The geometry of monoids; 2. Sheaves of monoids; 3. Logarithmic schemes; 4. Differentials and smoothness; 5. Betti and de Rham cohomology.

'Logarithmic geometry is a framework tailored for studying two fundamental aspects in algebraic geometry; compactification and degeneration. It has spectacular applications to p-adic Hodge theory, ramification, etc. Written by a top researcher in the field, this book deals with the foundation of the theory. Emphasis is placed on the geometry of monoids, on which log geometry is based, and on logarithmic smoothness, a key concept of the theory. The reader will be enabled to explore the fertile field.' Takeshi Saito, University of Tokyo