The current volume samples a selection of papers presented at the Geological Society of London meeting on ‘Biogeochemical Controls on Palaeoceanographic Proxies’, held at Burlington House, London, UK on 3–4 October 2005. The aim of the meeting was to bring together palaeontologists, geochemists and palaeoceanographers who could contribute evidence that, when considered together, would better constrain the proxies that are used for palaeoclimate reconstruction. An improved understanding and quantification of past climate change, and the processes that force climate to change, has a fundamental role to play in constraining model projections of future climate (e.g. Hegerl et al. 2006) but it remains a huge challenge. This is because key climate variables, such as temperature and ocean salinity, cannot be observed in a world which no longer exists, but must instead be teased from proxies in the geological and ice records. There are numerous proxy archives, but one of the most important, currently lying at the forefront of palaeoceanographic research, is the biogeochemical composition of sediment records. This publication consists of 11 papers which deal with various aspects of biogeochemical proxies and their interpretation in terms of past climate. Seven of these specifically focus on the Foraminifera. What are proxies? Primarily, these are biogenic components which have a close relationship to environmental parameters and may be identified as so-called ‘proxy variables’ (Wefer et al. 1999), providing measurable descriptors of key climatic and environmental variables. The methods commonly employed in palaeoceanography have their origins in the biological, chemical and physical sciences; palaeoceanography therefore represents a relatively young and truly crossdisciplinary field of research. At the time of writing, an excellent new book entitled Proxies in Late Cenozoic Paleoceanography has been published (Hillaire-Marcel & De Vernal 2007), providing a comprehensive review of the subject. This volume begins with an overview by James & Austin, highlighting some of the most important biological and geochemical proxies, and outlining their contribution to our understanding of the ocean–climate system. We anticipate that this review article will provide an accessible introduction to the topic as well as an insight into a wide range of analytical methods. The second paper by Williams highlights some of the fundamental features of the biomineralization process, initially contrasting these with inorganic mineral formation, before selecting examples from corals, foraminifera and coccoliths. The paper by Zeebe et al. develops a modellingbased approach to improve our understanding of stable carbon, oxygen, and boron isotopes as well as magnesium incorporation into foraminiferal calcite shells. The approach adopted by these authors is based on an integrated understanding of the inorganic chemistry, inorganic isotope fractionation, and biological controls that determine palaeo-tracer signals in organisms used in climate reconstructions. They argue very convincingly that the integration of laboratory experiments, field and culture studies, theoretical considerations, and numerical modelling holds the key to the method’s success. These authors demonstrate that a mechanism-based understanding is often required before primary climate signals can be extracted from the geological record, because these signals can be heavily overprinted by secondary, nonclimate related phenomena. One such phenomenon is foraminifer test diagenesis, which Pearson & Burgess highlight in their study of high-latitude Eocene sites. These authors illustrate the textures using a combination of reflected light microscopy and high-resolution scanning electron microscopy, highlighting the fact that foraminifer tests are prone to diagenetic recrystallization on a micron scale, which can affect their geochemical composition. For example, diagenetic calcite added on the sea floor or in shallow burial at low temperature, may result in the severe underestimation of the apparent tropical sea surface temperatures obtained from calcite foraminifera (e.g. Pearson et al. 2001). Next, two papers consider the growth rates and growth patterns in biogenic calcite. The first of these, by Schmidt et al. provides an overview of the effect of growth rate on the trace element