The Earth is an extremely dynamic system, with intimate links and feedbacks between the hydrosphere, atmosphere, biosphere, lithosphere and convecting mantle. The importance of the atmosphere as a geological agent was recognized as early back as Chamberlain (1897), but it has typically been neglected in research on past climates. Continental sediments and fossils are also somewhat neglected in the deep geologic record when it comes to linking that system with the oceanic carbon cycle and climate change. One proxy that may inherently link all these systems, which can be easily investigated, is through the analysis of stable-isotope ratios (traditional and non-traditional isotopes). This Special Issue does not include non-traditional stable isotopes, but the editors refer the reader to Johnson et al. (2004). Traditional stable isotopes are widely used in the biological, archaeological, ecological and geological communities, however, these research communities are only just becoming integrated in their scientific purpose.