To some extent, I find the idea of 'reading around' stress-inducingly vague: what qualifies as relevant? How far will I end up travelling down certain by-roads before realising that they are, for my purposes, dead ends? How do I know if I'm making progress? On the other hand, there's something deeply exciting about the prospect of all of the (for me) uncharted intellectual territory to be explored. During my time at Cambridge I used to love delving into the immense 'open stacks' of the (copyright deposit) University Library, not just to find a specific text but also to pause every now and then to let the sheer number of books written on so many fascinating topics sink in. One could never become laid back about the extent of one's own expertise when standing amidst so many overflowing shelves.
In terms of reading around my PhD topic, I've covered a lot of the most directly related texts, mainly thanks to the fact that there are not all that many books that touch upon the early modern history of reactions to mountains and mountain-climbing. So I'm now - with the aid of my supervisor - starting to think outside the box about areas of secondary reading that I should familiarise myself with. I've already worked on this topic during my MPhil year, but one side-effect of moving to a new institution for my PhD is that I'm finding myself encountering whole new areas of historical thought that I simply hadn't come across before. The Centre for Transnational History at St Andrews seeks to go beyond the boundaries of national histories and historiographies, a concept I am reasonably au fait with thanks to an undergraduate module on global history, but a recent workshop/reading group has raised the issue of spatial issues with relation to transnational history. I'm not entirely sure to what extent I would define myself as a 'transnational historian' - I'm not planning on writing a national history, but I'm also not sure if transnational flows / connections are going to be a main analytical focus for me - but spatial history in particular does seem very relevant and I launched into the suggested readings with much enthusiasm.
The readings were, it transpired during discussion, chosen partially because they represented a variety of different approaches to spatial/transnational history. A lot of the discussion focussed on the issue of 'visualisations' - from straightforward geographical maps all the way through to 'network visualisations' (which in a non-academic setting may be most familiar via the facebook fad a few years ago for such visualisations - does anyone remember the 'friend wheel' - image above - which demonstrated how many of your different friends knew one another?). I'm certainly intrigued by these sorts of tools - indeed, I'm attending another workshop on 'Making Simple Maps for Historians' - but more thought-provoking for me were the parts of the readings which elucidated the conceptual power of 'space' in historical research.
The part that really grabbed me was an overview of Henri Lefebvre's distinction between three different types of space - spatial practice, representations of space, and representational space. Spatial practice is how people use or move within space (for example, it is me getting up mid-blog post to brew a pot of tea, moving between my study and my kitchen via a corridor full of books, perhaps with a pause to glance at the shelves). Representations of space are what you would expect - the article I'm looking at includes the plans of architects, politicians, and surveyors under this bracket. I'm not sure whether this would include maps; the above all seem to be more concerned with potential shapings of space rather than records of space, but perhaps I'm wrong. Finally, representational space "is space as lived and experienced through a set of symbolic associations".  The article uses churches and synagogues as examples, as spaces which are deemed holy by the mental associations and symbolic importance that is attached to them. I would perhaps add that 'home' is a representational space, as what makes a house a home is how people view and understand a physical space in personal relation to themselves. 'My home' is not, and cannot ever be, 'your home', even if you inhabit as a guest the same physical space.
There's obviously a lot more to spatial history than can fit into one blog post, but Lefebvre's distinctions, for me, are the heart of the matter and the aspect that I really want to read up on and think about more. It's the area (or, the metaphorical 'space', if you will) between 'actual' physical space, and experienced or 'mentally shaped' (what Lefebvre calls representational space), which fascinates me. As a concept it has real relevance to the history of the landscape, and connects with ideas that have already been mooted in that field - that whilst a physical landscape may be relatively fixed, how people experience, view, and attach symbols to that landscape changes a great deal, not only over time, but from individual to individual. Bringing together the ideas of spatial history (both in terms of concept and in terms of visualisations) with the history of the landscape seems to me to be a a potentially very fruitful endeavour.
So this by-road in my 'reading around', at least, does not look set to become a dead-end.
 Richard White, What is Spatial History? http://www.stanford.edu/group/spatialhistory/cgi-bin/site/pub.php?id=29