From the reviews: "This new book goes far beyond anything currently available concerning variational principles in continuum mechanics. ... We have at hand a monument that all students and professionals in applied mathematics, physics and engineering will praise and naturally keep handy on their bookshelf. Teacher will find in the book a wealth of pedagogical material for many one- semester courses. They and their students will appreciate the clarity simplicity and ingenuity of many arguments offered without pedantry and sacrifice of rigour." (Gerard A. Maugin, Mathematical Reviews, Issue 2011 a)