Introduction to the Calculus of Variations

This book is neither too naive nor too brief, still I was able to read more than 80 pages in one day, simply because it is written very clearly. An excellent introduction in Calculus of variations, very concise and very clear. Some context is devoted to control theory, which can be considered as a generalization of calculus of variations. The part on field embedding and Hilbert invariant integral is perfectly wriiten, actually the best that I have ever encountered.

I used this book as a compliment to a Theoretical Mechanics course. The section on Hamilton's equations is especially well written. Although probably more mathematically rigorous than anything I needed, the style is so silky smooth that anyone interested in mathematical physics will surely enjoy it. And it will be a surprise for many to find that the "proof" of equivalence between the Lagrangian and Hamiltonian formulations presented in most texts is half incomplete. The book is complemented by good examples, clear notation and quite a number of graphics. Of course, proofs and arguments are absolutely rigorous, but well explained. This is a mathematics text, after all. I strongly recommend it, as well as any other of Sagan's books.

This book is a more thorough treatment of the calculus of variations than some of the other books on the subject that you could buy. It's bit more expensive... I especially reccomend this book if you like Sagan's other book "Boundary and Eigenvalue Problems in Mathematical Physics". If you like his style of writing, and I do, he again shows nice touch of explaining the material in writing and then with examples. A good book with a nicely written and more thorough treatment of the subject (unless you want a full price text that is)..