All sources are to be used critically; think about who is writing and what their agenda is. Be explicit about this in your essay. Remember also to check the Archaeology referencing guidelines.
Key article (required reading)
Campbell, S., 2013. Metal detecting, collecting and portable antiquities: Scottish and British perspectives. Internet Archaeology 33. http://intarch.ac.uk/journal/issue33/1/index.html
Open Archaeology topical issue on non-professional metal-detecting in Europe (scroll down list of contents and you'll find it)
If you're interested in the role of metal detecting in battlefield archaeology, you should look at the work of Natasha Ferguson, who has articles in both of those issues.
Dobat, A. S. 2012. Between Rescue and Research: An Evaluation after 30 Years of Liberal Metal Detecting in Archaeological Research and Heritage Practice in Denmark. European Journal of Archaeology 16(4): 704-725. (e-journal)
Gill, D.W.J. 2010. The Portable Antiquities Scheme and the Treasure Act: Protecting the Archaeology of England and Wales? Papers from the Institute of Archaeology 20, 1–11. (online)
Pollard, T. 2009. The rust of time: metal detecting and battlefield archaeology, in Thomas, S., & Stone, P. G. (Eds.). (2009). Metal detecting and archaeology. Ipswich: Boydell Press. (Library: High Demand)
Rasmussen, J. M. 2014. Securing cultural heritage objects and fencing stolen goods? A case study on museums and metal detecting in Norway. Norwegian Archaeological Review 47(1): 83-107. (e-journal)
Robbins, K. J. 2013. Balancing the Scales: Exploring the Variable Effects of Collection Bias on Data Collected by the Portable Antiquities Scheme. Landscapes 14(1): 54-72. (e-journal)
Thomas, S. 2012. Searching for answers: a survey of metal-detector users in the UK. International Journal of Heritage Studies 18:1, 49-64. (e-journal)
Thomas, S. and P.G. Stone (eds). 2009. Metal detecting and archaeology. Boydell Press. (Library: High Demand)
Web resources - for metal detectorists as well as archaeologists...
An Assessment of the Extent and Character of Hobbyist Metal Detecting in Scotland
Prepared for Historic Environment Scotland by GUARD Archaeology Ltd (published 31 Jan 2017). Note particularly the case studies, conclusions and recommendations.
UK Detector Net
A site with a wide range of resources for metal detectorists.
National Council for Metal Detecting
"A representative body of elected volunteers formed in 1981 to provide a means whereby responsible metal detector users would have a democratic forum to discuss problems affecting the hobby and to provide an authoritative voice to counter ill -informed and frequently misleading criticism of the hobby. It does not represent the trade or archaeological interests" Includes a code of conduct. The Code of Practice for Responsible Metal Detecting in England and Wales (PDF) was recently published and supported by a wide range of organisations.
Queen's and Lord Treasurer's Remembrancer
What does he do? Click and find out...
Treasure Trove Scotland
Treasure Trove ensures that significant objects from Scotland's past are preserved in museums for public benefit. These pages are intended to act as a guide for finders, museums and the general public to the Treasure Trove process. They also have a Facebook page.
For examples, it's worth going to reputable news sites (Guardian, BBC etc) and searching for terms like 'metal detector'. This should give you a range of reasonably reliable reports which look at various perspectives, not just the detectorists or the archaeologists.
Also, do your own searches: library catalogue; when you find one book on the shelf, browse the books next to it; web searches (be critical!); Google Scholar; etc.
Key essay-writing tips
• Create an argument which addresses the question explicitly and thoughtfully
• Create a structure which orders that argument clearly and coherently; use signposts (e.g. subheadings or first sentences of paragraphs) to tell the reader where you are in that structure
• Support your argument with evidence – examples, case studies, references
• Make the essay your own. It’s a very broad question, and there is no restriction on what you use as examples (other than relevance!). Look for approaches, examples and conclusions that really express what you think is interesting and important.
• Be scrupulous about referencing – see the Archaeology referencing guidance for how to do it.
• Go to the tutorial on essay preparation.