One of the general tasks in science and engineering is to record measured signals and get them to tell us their 'secrets" (information). These signals vary over time and may be periodic or aperiodic, noise or also superpositions of components. Anyway, what we are measuring is a conglomerate of several components, which means that effects caused by the measuring-devices' electronics and, for example, noise, get added to the signal we're actually after. Meant to serve as an "amusing textbook," this book is written for all students and practitioners who deal with Fourier transformation. Fourier series as well as continuous and discrete Fourier transformation are covered, and particular emphasis is placed on window functions. Many illustrations and easy-to-solve exercises make the book especially accessible, and its humorous style will add to the pleasure of learning from it.