"Book under review is enormous in scope and contains most of the old and current results on extension problems. Many of the theorems appear here for the first time in book form. The book is self-contained, and the detailed arguments make it accessible to a wide audience, especially graduate students interested in getting into the subject. ... It will become a standard reference in the subject, and it deserves a spot in the library." (Garving K. Luli, Bulletin of the American Mathematical Society, Vol. 53 (1), January, 2016) "The two-volume monograph is divided into ten chapters, with five chapters in each volume. ... Volume II reports on the recent progress in the area of the extension and trace problems. ... the book successfully conveys the authors' coherent vision for the subject, with the emphasis on linear extension operators, finiteness properties, and the treatment of extension via selection. It is certain to become a standard reference in the field." (Leonid V. Kovalev, Mathematical Reviews, Issue 2012 j)

• Part 3. Lipschitz Extensions from Subsets of Metric Spaces.- Chapter 6. Extensions of Lipschitz Maps.- Chapter 7. Simultaneous Lipschitz Extensions.- Chapter 8. Linearity and Nonlinearity.- Part 4. Smooth Extension and Trace Problems for Functions on Subsets of Rn.- Chapter 9. Traces to Closed Subsets: Criteria, Applications.- Chapter 10. Whitney Problems.- Bibliography.- Index.

"Book under review is enormous in scope and contains most of the old and current results on extension problems. Many of the theorems appear here for the first time in book form. The book is self-contained, and the detailed arguments make it accessible to a wide audience, especially graduate students interested in getting into the subject. ... It will become a standard reference in the subject, and it deserves a spot in the library." (Garving K. Luli, Bulletin of the American Mathematical Society, Vol. 53 (1), January, 2016) "The two-volume monograph is divided into ten chapters, with five chapters in each volume. ... Volume II reports on the recent progress in the area of the extension and trace problems. ... the book successfully conveys the authors' coherent vision for the subject, with the emphasis on linear extension operators, finiteness properties, and the treatment of extension via selection. It is certain to become a standard reference in the field." (Leonid V. Kovalev, Mathematical Reviews, Issue 2012 j)

• Part 3. Lipschitz Extensions from Subsets of Metric Spaces.- Chapter 6. Extensions of Lipschitz Maps.- Chapter 7. Simultaneous Lipschitz Extensions.- Chapter 8. Linearity and Nonlinearity.- Part 4. Smooth Extension and Trace Problems for Functions on Subsets of Rn.- Chapter 9. Traces to Closed Subsets: Criteria, Applications.- Chapter 10. Whitney Problems.- Bibliography.- Index.

"Book under review is enormous in scope and contains most of the old and current results on extension problems. Many of the theorems appear here for the first time in book form. The book is self-contained, and the detailed arguments make it accessible to a wide audience, especially graduate students interested in getting into the subject. ... It will become a standard reference in the subject, and it deserves a spot in the library." (Garving K. Luli, Bulletin of the American Mathematical Society, Vol. 53 (1), January, 2016) "The two-volume monograph is divided into ten chapters, with five chapters in each volume. ... Volume II reports on the recent progress in the area of the extension and trace problems. ... the book successfully conveys the authors' coherent vision for the subject, with the emphasis on linear extension operators, finiteness properties, and the treatment of extension via selection. It is certain to become a standard reference in the field." (Leonid V. Kovalev, Mathematical Reviews, Issue 2012 j)

• Part 3. Lipschitz Extensions from Subsets of Metric Spaces.- Chapter 6. Extensions of Lipschitz Maps.- Chapter 7. Simultaneous Lipschitz Extensions.- Chapter 8. Linearity and Nonlinearity.- Part 4. Smooth Extension and Trace Problems for Functions on Subsets of Rn.- Chapter 9. Traces to Closed Subsets: Criteria, Applications.- Chapter 10. Whitney Problems.- Bibliography.- Index.