Pd was initiated by American software engineer Miller Puckette, who previous co-developed the well known and similarly structured software Max/Msp. Pd is not commercial software; i.e., it was not developed by a corporation and is not for sale. Instead, it is &#8220;open source&#8221;: its source code is not the (patented) property of a corporation, but is rather freely available to all. One drawback to this is that a detailed operating manual for users who lack programming experience has not existed until now. In contrast to a corporation&#8212; which has a monetary interest in ensuring that first-time users can easily operate new software&#8212;the open source movement lacks such a driving force to make itself accessible. This book is an attempt to fill that gap. Loadbang is designed for self-study, principally for composers. It begins with explanations of basic programming and acoustic principles then gradually builds up to the most advanced electronic music processing techniques. The book&#8217;s teaching approach is focused primarily on hearing, which we consider a faster and more enjoyable way to absorb new concepts than through abstract formulas. The patches described are available for download.