A first practical guide to Fortran 90 by members of the X3J3 Committee. This is a tutorial on Fortran 90 for programmers and engineers and scientists who work with Fortran 77 and need to learn the heavily revised standards provided for in Fortran 90. Covered in this guide to programming languages are basic principles, simple programming exercises, numerous examples and problems. Written by four senior members of the ANSI Fortran Standards Committee X3J3, this book serves as a quick source of information for practising professionals.