Acknowledgments

A book that teaches a seventy-year-old language stands on an enormous amount of work by other people, and it would be wrong not to name it.

Our first debt is to the Fortran standards committees, J3 and WG5, whose patient, unglamorous work across decades turned FORTRAN 77 into the genuinely modern language this book teaches. Every intent, every allocatable array, every coarray in these pages exists because a group of people argued it through, carefully, so that the code you write today will still compile in thirty years.

We are indebted to the authors of the works this book learns from and points you toward — above all Stephen Chapman's Fortran for Scientists and Engineers, Metcalf, Reid, and Cohen's Modern Fortran Explained, and Milan Curcic's Modern Fortran. Where we teach well, we are often standing on their shoulders; where we fall short, the fault is ours.

This book would recommend far less if the fortran-lang community had not spent the last several years rebuilding Fortran's open-source ecosystem in public: the Fortran Package Manager, the Standard Library, the online playground, the LFortran compiler, and the discourse forum where beginners' questions are answered with unusual generosity. They are the living proof of the book's central claim — that Fortran is not a relic but an active, improving language.

We thank the maintainers of GCC/gfortran, without whose free, high-quality, universally available compiler a free Fortran textbook would be a contradiction; and the authors and maintainers of LAPACK, BLAS, FFTW, NetCDF, HDF5, OpenMP, and MPI, the shared foundations on which computational science is built, several of them written — of course — in Fortran.

Finally, we thank the working scientists and engineers who keep the world's simulation codes running, often without recognition, frequently in Fortran, and the students who inherit those codes and choose to understand them rather than discard them. This book is for you.

Errors that remain are ours. This is a living document under a Creative Commons license; corrections and improvements from readers are welcome and gratefully credited.