Traveller is a series of related science fiction role-playing games. Traveller20 (or T20) is the d20 System-version of Traveller, developed by Quicklink Interactive. Task checks roll a twenty-sided die (d20). The roll must be equal to or above the target number, for success. This volume is subtitled 'The Traveller's Handbook' and is not a standalone game system. To play T20 requires a game core book published by 'Wizards of the Coast', and the following types of dice : four-sided, six-sided, eight-sided, ten-sided, twelve-sided and twenty-sided. Marc Miller, the creator of the award winning Traveller science-fiction universe, says in his introduction that Traveller is about travel (extending beyond daily lives), the human condition, consequences of actions, danger, risk and reward, and about goals (setting your own and pursuing them at your own pace). This heavy book is in fine condition with only a few light handling marks.