The fifth volume of the British philosophy journal Collapse, published by Urbanomic, 2008. Collapse IV features a series of investigations by philosophers, writers and artists into Concept Horror. Contributors address the existential, aesthetic, theological and political dimensions of horror, interrogate its peculiar affinity with philosophical thought, and uncover the horrors that may lie in wait for those who pursue rational thought beyond the bounds of the reasonable. Contributors to this issue include Thomas Ligotti, China Miéville, Reza Negarestani, Quentin Meillassoux, Jake and Dinos Chapman, et al.