Book excerpt: The introduction of the Fortran 90 standard is the first significant change in the Fortran language in over 20 years. this book is designed for anyone wanting to learn Fortran for the first time or or a programmer who needs to upgrade from Fortran 77 to Fortran 90. Employing a practical, problem-based approach this book provides a comprehensive introduction to the language. More experienced programmers will find it a useful update to the new standard and will benefit from the emphasis on science and engineering applications.