Like it or not, IT Projects have been plagued by poor success rates, largely due to the poor elicitation and analysis of user requirements. Further, a heavy reliance upon prior experience among professionals using extant methods has impeded the entry of newly qualified analysts and designers to the industry, further reducing productivity and success rates. The Activity Theoretic Systems Architecture methodology (ATSA) is designed to provide end-to-end systems analysis and design guidance, with techniques that can be modified and lightened as analyst experience grows. This volume presents the book which details the driving philosophy, underlying theory and the development narrative of ATSA in its original form, together with a brief overview of the latest Object Oriented variant, ATSA: OO in its final appendix.