After looking through most of the available texts, we chose
this this book to teach a course on Fortran-90 to scientists and engineers at NASA. It is especially helpful to programmers with a good understanding of Fortran-77 who want to make the transition to this powerful revision of the language. The book covers the most useful new features (array processing, allocateable memory, derived types, encapsulation) very thoroughly. The writing is generally clear, cogent, and understandable. The only thing lacking is a complete treatment of language intrinsic functions, for which you need the large (and expensive) language handbook.