Valued fields - Antonio J Engler

Absolute values and their completions - such as the p-adic number fields - play an important role in number theory. Krull's generalization of absolute values to valuations made possible applications in other branches of mathematics. In valuation theory, the notion of completion must be replaced by that of "Henselization". This book develops the theory of valuations as well as of Henselizations, based on the skills of a standard graduate course in algebra.

From the reviews:

"The book starts with the basic notion of absolute values followed by a comprehensive introduction to the theory of Krull valuations of arbitrary rank leading eventually to some deep results of recent research. … A useful feature of the book are its two appendices dealing with classification of V-topologies and ultraproducts of valued fields. The concise style and choice of material makes this book a wonderful reading. It is a unique, original exposition full of valuable insights." (Sudesh Kaur Khanduja, Zentralblatt MATH, Vol. 1128 (6), 2008)