ABZ 2010 was held in the beautiful natural setting of Orford in the Eastern Townships of Qu´ ebec, during February22-25,2010, midwaythroughthe Ca- dian winter and the 21st Winter Olympics, bringing participants from all over the world to brave this rigorous climate. ABZcoversrecentadvancesinfourequallyrigorousmethodsforsoftwareand hardware development: Abstract State Machines (ASM), Alloy, B and Z. They shareacommonconceptualframework, centeredaroundthe notionsofstateand operation, andpromotemathematicalprecisioninthemodeling, veri?cation, and construction of highly dependable systems. These methods have continuously matured over the past decade, reaching a stage where they have been successfully integrated into industrial practice in various areas like trains, automobiles, aerospace, smart cards, virtual machines, and business processes. Their development is in?uenced by both research and practice, which mutually nurture each other. ABZ has both a long and a short history. With the aim of stimulating cro- fertilization between these four methods, it has merged their individual conf- ence and workshopseries which started in 1986 for Z, 1994 for ASM, 1996 for B, and 2006 for Alloy. The ?rst ABZ conference was held in London in 2008; ABZ 2010 is the second edition. The conference remains organized as four separate Program Committees.