Many of the past titles have long been out of print and yet are still of value for reference purposes. English Heritage is now making these titles available as ebooks (see the English Heritage Publishing catalogue for details) and as PDFs which can be downloaded for free from the ADS English Heritage Archaeological Monographs archive page:
http://archaeologydataservice.ac.uk/archives/view/eh_monographs_2014/
At present, the ADS holds 84 titles covering a wide range of subjects, periods and specialisms. Some of the country’s most iconic heritage sites are represented including Stonehenge, Hadrian’s Wall and York Minster and with subjects ranging from a Saxon bed burial to coastal fortifications; radiocarbon dating to an architectural history of English prisons, there’s plenty to explore!