Professional electronic edition, and student eBook edition (freely installable PDF with navigational links), available from diestel-graph-theory.com

This standard textbook of modern graph theory, now in its sixth edition, combines the authority of a classic with the engaging freshness of style that is the hallmark of active mathematics. It covers the core material of the subject with concise yet reliably complete proofs, while offering glimpses of more advanced methods in each field by one or two deeper results, again with proofs given in full detail.

The book can be used as a reliable text for an introductory course, as a graduate text, and for self-study.

New in this 6th edition:

Two new sections on how to apply the regularity lemma: counting lemma, removal lemma, and Szemerédi's theorem.

New chapter section on chi-boundedness.

Gallai's A-paths theorem.

New or substantially simplified proofs of:

 - Lovász's perfect graph theorem

 - Seymour's 6-flow theorem

 - Turán's theorem

 - Tutte's theorem about flow polynomials

 - the Chvátal-Erdös theorem on Hamilton cycles

 - the tree-of-tangles theorem for graph minors (two new proofs, one canonical)

 - the 5-colour theorem

Several new proofs of classical theorems. Many new exercises.

From the reviews: 

“This outstanding book cannot be substituted with any other book on the present textbook market. It has every chance of becoming the standard textbook for graph theory.” Acta Scientiarum Mathematicarum 

"Deep, clear, wonderful. This is a serious book about the heart of graph theory. It has depth and integrity." Persi Diaconis & Ron Graham, SIAM Review 

“The book has received a very enthusiastic reception, which it amply deserves. A masterly elucidation of modern graph theory.” Bulletin of the Institute of Combinatorics and its Applications 

“Succeeds dramatically… a hell of a good book.” MAA Reviews 

“A highlight of the book is what is by far the best account in print of the Seymour-Robertson theory of graph minors.” Mathematika 

“…like listening to someone explain mathematics.” Bulletin of the AMS