  This volume contains the proceedings of the Second International Workshop
Hybrid Systems and Biology (HSB 2013) held in Taormina (Italy), on September
2th, 2013. The workshop is affiliated to the 12th European Conference on
Artificial Life (ECAL 2013).
  Systems biology aims at providing a system-level understanding of biological
systems by unveiling their structure, dynamics and control methods. Due to the
intrinsic multi-scale nature of these systems in space, in organization levels
and in time, it is extremely difficult to model them in a uniform way, e.g., by
means of differential equations or discrete stochastic processes. Furthermore,
such models are often not easily amenable to formal analysis, and their
simulations at the organ or even at the cell levels are frequently impractical.
Indeed, an important open problem is finding appropriate computational models
that scale well for both simulation and formal analysis of biological
processes. Hybrid modeling techniques, combining discrete and continuous
processes, are gaining more and more attention in such a context, and they have
been successfully applied to capture the behavior of many biological complex
systems, ranging from genetic networks, biochemical reactions, signaling
pathways, cardiac tissues electro-physiology, and tumor genesis. This workshop
aims at bringing together researchers in computer science, mathematics, and
life sciences, interested in the opportunities and the challenges of hybrid
modeling applied to systems biology.
  The workshop programme included the keynote presentation of Alessandro
Astolfi (Imperial College of London, UK) on Immune response enhancement via
hybrid control. Furthermore, 8 papers were selected out of 13 submissions by
the Program Committee of HSB 2013. The papers in this volume address the hybrid
modeling of a number important biological processes (iron homeostasis network,
mammalian cell cycle, vascular endothelial growth factor (VEGF), genetic
regulatory network in mammalian sclera) and, the formalisms and techniques for
specifying and validating properties of biological systems (such as,
robustness, oscillations).
