This is an important book, although technically speaking it is not a book at all. But if one has carried it while travelling it certainly feels like one: almost 500 pages printed on heavy paper in a good paperback cover. It should probably figure on the shelves of most archaeologists and certainly those who have a role in management decisions with long-term implications for archaeological sites. Technically, however, it is four numbers in one volume of the journal Conservation and Management of Archaeological Sites, and those with access to the Ingenta databases can also find it online. The volume contains an editorial and 41 contributions; the proceedings of the 4th International Conference on Preserving Archaeological Remains In Situ, which went under the acronym PARIS 4, held at the National Museum of Denmark in Copenhagen in May 2011. I regretted that I could not attend the conference at the time, but I and others have quickly been compensated when this volume arrived at the end of 2012, some 18 months after the event. The organizers, editors, contributors and reviewers are to be applauded for this. It almost took me longer to read—the information is dense and not necessarily written to read as a novel. Reviewing 42 entries in 2000 words would mean less than 50 words for each. So, rather, I take the quality of the contributions and the research that lies behind them for granted, and I will do the same for the editing. I have only spotted occasional mistakes in dates and references, I will therefore comment on a few contributions that struck me, and use the content of the others as a ‘proxy’ for directions that our discipline is taking and how these influence present-day research, management and funding.

The book is organized in four sections, see table of contents. The first deals with the theme of degradation and addresses natural processes, laboratory and field experiments, and humanly induced effects: nine articles in all and 27 authors. In many ways the theme is continued in the last section, theme 4, which tries to resolve the question of whether the effectiveness of preservation in situ can be documented, and whether measures to reduce microbial and chemo-physical degradation can be improved. Theme one covers corrosion under different soil circumstances, reburial and its aerating effects, base-line studies and time series, bio-erosion of stone artefacts in sediment-lean underwater environments, compaction of deep layers of wetland sediments under the point-load of modern construction, the environmental impact, and, by consequence, the effect on archaeological remains of commonly used wood preservatives in wetland environments. At a different level, the latter should in effect be a warning against more than very restrictive use, for very restricted time periods, of sacrificial or otherwise toxically degradable substances and appliances to counter degradation of archaeological sites in underwater or groundwater environments. Particularly thought-provoking is an article on modelling the environmental friendliness of managing the ‘carbon footprint’ and flood-plain control from observations at Star Carr.

The second theme goes under the title ‘Monitoring and Mitigation case studies’ and has 15 articles from 48 authors. As can be expected it is even more of a mixed bag than the first section, but it is good stuff. Although presented as case studies, some of it is fundamental modelling of processes, some of it sits at the interface between dealing with invisible, buried and hardly known archaeological remains and the integrated conservation of architectural remains; of accessibility, enjoyment and tourism management, both under water and above. Some are really case studies and the geographical spread is wide. Scandinavia and Northern Europe are evidently well represented at a Copenhagen conference, but Italy, Australia, New Zealand, China and the Emirates figure as well. It is clear that monitoring has become as central an issue in archaeological heritage management as in any other field, and it is equally clear that scientific thinking and approaches have been boosted enormously to serve that need. Nevertheless, reading the section makes me jump on some of my hobby horses. One is that sharing heritage is crucial: accessibility and enjoyment is key, in the museum, in publications, on the net, but also in the field. Managing accessibility calls for monitoring and for mitigation, and a range of these case studies address that. Mitigation of adverse effects, be they visitor induced or deriving from natural causes, is part of that game, part of any coherent management strategy.

In the underwater domain, wreck trails, public archaeology and conscious management of accessible sites have fortunately developed all around the world. In this book it is some solid Italian work that stands out in the context of accessible public archaeology. The aim of mitigation is to preserve as much as possible as is. Clearly, there is nothing wrong with that and great progress has been made. What I am worried about is that the word ‘mitigation’ is only interpreted in that very specific sense. That more and more attention—research and management alike—is diverted from the other meaning of mitigation; making the best of what cannot be preserved through collection and analysis of data that informs us on the past in novel and creative ways. This worry does not apply at all to archaeology on land where mitigation of development processes may have its issues, but nevertheless feeds into a wide range of research approaches. But it does apply to the maritime environment, where even development-led research is far too often reduced to a graphical reproduction of a site's condition without knowing what the affected site actually was, or, even worse, by labelling it with unsubstantiated inferences from other than field data. The problem is even more prominent where the dynamics of the environment are such that mitigation is about immediate observation and assessment, and also about deferring the need of immediate action to gain the time necessary to develop a proper research and management design for relevant on-site work and for securing funding. In that sense I find it very important that the editors decided to include a contribution by Daniel Pascoe on Stirling Castle (1703) and other Goodwin Sands wrecks. It is not a new story, but it is exemplary of the half-hearted response of a half-hearted policy that leads to paper preservation for preservation's sake; and of monitoring and ‘mitigation’ that leads to an understanding of the degradation history of the past few decades, but leaves everyone empty-handed as to what could have been learned in terms of ship-archaeology and history from the lost remains and their distribution. It is perhaps not fair to criticize approaches that were started many decades ago, but has the situation really improved? Half-hearted and makeshift policies are what contribute most to the misunderstandings surrounding the principles of in situ preservation in underwater cultural heritage (UCH) management (Maarleveld, 2011, Open letter to Dr Sean Kingsley, Wreck Watch International, regarding his questionnaire on in situ preservation. Journal of Maritime Archaeology 6, 107–11). The now almost forgotten Rooswijk scandal of 2005 refers to exactly the same region, policy and environment as Stirling Castle.

The next section, with 7 articles by 10 authors, is devoted to the third theme. It starts with an essay ‘Take the Right Decision Everybody’. It is not as imperative and worrying as such a title suggests considered under the theme's heading: ‘Protocols, Standards and Legislation’. In fact the article addresses the role of monitoring in informing decision-making, and making it possible to ‘take the right decision’. The example used is the World Heritage site of Bryggen in Bergen, Norway, where the ‘big ship of Bergen’, ranges of masts and head beams and other medieval ship parts were uncovered. Another article discusses the necessity for standards in interpreting soil characteristics to compare monitoring results from different burial environments. Nevertheless, this section is the least coherent part of the book. Sustainable management of dendro-sample archives, the creation of a monitoring organization in Belgium, and the cost-effectiveness of heritage preservation are some of the issues that are addressed. One paper cites the Burra Charter of 1979 and the preservation of floor mosaics in Turkey; and opens up the tension between ideals-and-principles and legislation-and-practical-impediments. The Burra Charter is a mightily inspirational document of great influence worldwide on conservation practices. I am not sure how well it, or the Nara Document on Authenticity (1994) cited elsewhere, are known in circles of European archaeologists except those directly involved in the World Heritage programmes.

The last section, theme 4, 10 articles by 23 authors, is the core of the endeavour. It is here that the editors and others present their long-term approaches to the monitoring and preservation of the unexcavated parts of the Nydam Mose site, where the Nydam boat was excavated in 1859 and major excavations were carried out between 1989 and 1997. It is here that the Somerset peatlands, and the never-ending story of changing water tables and flood-control in the Netherlands, illustrated by the Schokland World Heritage site, can be compared. It is here also that the complicated story of the Rose Theatre, London, is retold in the context of preservation in situ. Although reported in a matter-of-fact way, it brings back all the reminiscences of the heated debate and the continuing story of experiencing the site's significance; ‘Excavation’, archaeological management and continuous monitoring ‘as Theatre’ in optima forma (Tilley, C., 1989, ‘Excavation as Theatre’, Antiquity 63, 275–280). There are other positive contributions: a short story of 150 years of integrated conservation in London; one of 30 years of monitoring in England; a somewhat superficial overview of solving dilemmas related to the management of UCH sites worldwide; and a survey of visitor experience at colonial sites in Australia and New Zealand.

An article under the fascinating double title: ‘Is Preservation in Situ an unacceptable Option for Development Control? Can Monitoring Prove the Continued Preservation of Waterlogged deposits?’ deals with organizational issues and guidance that define what is and can be monitored, followed by a nice comparative study relating to the second question. But what of the first? Here ‘unacceptability’ refers to the way guidance notes are to be interpreted and therefore, indirectly, to the system of financing development-led interventions, which is at odds with providing budgets for long-term monitoring and management. Although the issue is only lightly touched on in this article, the financing of development-led interventions is of fundamental importance, and this can be read between the lines of many other contributions. The book shows that enormous progress has nevertheless been made, and that the research community has been successful in securing funds for joint research programmes that give us a better understanding of both degradation and preservation. For underwater work this is an enormous asset, and, an enormous improvement compared to, say, 15 years ago. The production of this worthwhile book is a major achievement and despite or because of its wide variety and range. However, I am wary of too much satisfaction, especially in relation to the underwater environment. Understanding how heritage decays is not the same as making good use of it. Managers and funding bodies should know that. But do they? Direct archaeological research is an equally important avenue to mitigation as trying to control natural processes, which in the end can only be done to a very limited extent. Technocratic solutions are an easy priority for funding bodies, developers, agencies and researchers alike. When archaeology under water was a nascent discipline, and this Journal came into being, diving and fieldwork technology had all the attention, whereas preservation technology was overlooked. But important as both may be, they are accessory; they should not be seen as the easy option.