The presence on the market of more and more user friendly structural analysis software takes to the fact that a Finite Element code user is not always prepared to dress the stress engineer clothes. Facing this situation from a cultural point of view is not certainly easy, above all when economic interests are present and therefore the vendors tend to highlight the simplicity of using a modern program and to hide the possible dangers and the sources of possible errors. Everyone will agree with the fact that knowing the use of CAD software for technical drawing, i. e. knowing the way to generate graphical entities, will not make the user a designer; in the same way the knowledge, supported by modern structural codes, in building a finite element model will not make anyone a structural engineer. The idea of this book borns from here. These pages want to be a guide in order to give the instruments to the user that, for any reason, has to face the automatic structural calculation. Obviously the book just touches the surface of a problem which is very big and complex (many references to important aspects are not treated, such as instability, modal analysis and, last but not least, non linear analysis). Nevertheless we hope that this job will contribute, even if as a minimal part, to fill up the voids present in the “classical texts” that prefer to deal with the theory despite of the practical aspects.