Patricio Felmer is a mathematician working at the University of Chile, specialized in the area of Partial Differential Equations. During the last years he has contributed to Mathematics Education, working in projects for the Chilean government on the definition of Standards for the Formation of Mathematics Teachers and on the development of material for them. Lately he has been working in R&D projects aiming to implement professional development strategies based on problem solving for in-service teachers. Dr. Erkki Pehkonen is a full professor (emer.) in the field of mathematics and informatics education in the Department of Teacher Education at the University of Helsinki in Finland. He is interested in problem solving with a focus on motivating middle grade pupils, as well as in understanding pupils’ and teachers’ beliefs and conceptions about mathematics teaching.Jeremy Kilpatrick is Regents Professor of Mathematics Education at the University of Georgia.  He has taught at European and Latin American universities, receiving four Fulbright awards.  He holds an honorary doctorate from the University of Gothenburg and is a Fellow of the American Educational Research Association, a National Associate of the National Academy of Sciences, and a member of the National Academy of Education.   He received a Lifetime Achievement Award from the National Council of Teachers of Mathematics and the 2007 Felix Klein Medal from the International Commission on Mathematical Instruction.  His research interests include proficiency in mathematics teaching, curriculum change and its history, assessment, and the history of research in mathematics education.

• Introduction.- Does the Textbook Support the Implementation of Mathematical Problem-Posing in Classrooms?.- Problem Posing and Questioning.- Effective Factors and Beliefs About Mathematics of Chilean Young Children.- Reformulating: Mathematical Problem Solving as Inquiry.- Improving Mathematical Problem-Solving.- Reaction Paper.-Teaching Mathematical Problem Solving in Hungary for Students Who Have Average Ability in Maths.- Exploratory Problems as Propositions for Doing Mathematics.- On the Role of Corporeality, affect, and metaphoring in Problem Solving.- Building Thinking Classrooms: Conditions for Problem Solving.- Research Project Finland-Chile on Open Problem Solving in elementary Mathematics Teaching.- The Coordinated Use of Several Digital Technologies to Frame and Foster Learners' Mathematical Problem Solving Experiences.- Proportional Word Problem Solving Through a Modelling Lense.- Conceptual Model-Based Problem Solving.- Reaction Paper.- Novel Chilean Secondary MathematicsTeachers as Problem Solvers.- Infusing Mathematical Problem Solving in the Mathematics Curriculum.- Mathematical Problem Posing in Taiwan.- Mathematical Problem Solving and Teacher Professional Learning.