For the existing user of Fortran77 who wants to understand Fortran90, this is the best book that I have found (and I have read at least another six books on Fortran90). It has good coverage of the difficult areas such as the use of dynamic storage, data structures, user-defined operators, and KIND values. There are also lots of examples to aid understanding. I found hardly any errors in the text (unlike several other books on the subject). I have recommended it to several of my colleagues, a number of whom have also bought it. It probably isn't suitable for someone with no programming experience, but for someone with at least a slight familiarity with older Fortran, it is excellent.