Chaosium's Basic Roleplaying is a core rulesbook that gathers in one place the rules, modules, and options for one of the original and most influential role playing gaming systems in the world. Basic Roleplaying is designed to be intuitive and easy to play. While character attributes follow a 3D6 curve, most of the other Basic Roleplaying mechanics are even simpler. Virtually all rolls determining success or failure of a task are determined via the roll of percentile dice. The core virtues of the system are timeless. Primary characteristics of Basic Roleplaying that have emerged from decades of play, across many different varieties of the system are as follows: the system is remarkably friendly to newcomers, and it is easy to describe the basics of the game system, and the percentile mechanics, to non-gamers. Players of other game systems often find Basic Roleplaying to be much less mechanistic and less of a barrier to the actual act of roleplaying. Less time spent on game systems usually equals more time available for roleplaying and thinking in character. Most of the information players need to know is present on their character sheets. Characters tend to evolve based on practicing the skills they use the most. They do not arbitrarily gain experience in skills and qualities based on ephemeral elements such as levels or experience ranks. Combat can be very quick and deadly, and often the deciding blow in a conflict is the one to land first. Basic Roleplaying is remarkably modular: levels of complexity can be added or removed as needed, and the core system works equally well with considerable detail as it does with a minimal amount of rules. The internal consistency of Basic Roleplaying allows for rules judgments to be made rapidly and with little searching through the rulebook for special cases. This book represents a first for Basic Roleplaying: a system complete in one book, without a defined setting. Previously, Basic Roleplaying has been an integral part of stand-alone games, usually with rich and deep world settings. Due to differences in these settings, Basic Roleplaying has had many different incarnations. Variant and sometimes contradictory rules have emerged between versions, to better support one particular setting over another. Chaosium's Basic Roleplaying system reconciles these different flavors of the system and brings many variant rules together into the covers of one book, something that has never been done before. Some of these rules are provided as optional extensions, some as alternate systems, and others have been integrated into the core system. By design this work is not a reinvention of Basic Roleplaying or a significant evolution of the system, but instead a collected and complete version, without setting, provided as a guide to players and gamemasters everywhere and compatible with most Basic Roleplaying games. It also allows the gamemaster the ability to create his or her own game world (or worlds), to adapt others from fiction, films, or even translate settings from other roleplaying games into Basic Roleplaying.