I've just put in a massive order at Abebooks (which links the catalogues of many secondhand booksellers from around the world). This is not something I will be able to afford to do often, but at the moment I am still working full-time so it is sort of affordable. One thing I've found out that is that even if you choose the slower, cheaper postage option, it usually doesn't take anything like the estimated 21-36 (or more) working days to get to Australia, but more like a week or two - so it's not really worth going for the faster, more expensive postage unless you really, really needed it yesterday.
Most of the books are primary sources, particularly British novels from the interwar period featuring predictions of massed air raids on cities, ranging from the relatively well known (eg Nevil Shute's What Happened to the Corbetts (1939), Harold Nicolson's Public Faces (1932)) to the delightfully obscure (eg Bernard Newman's Armoured Doves: A Peace Novel (1931), or Leslie Pollard's Menace: A Novel of the Near Future (1935). There are also some non-fictional works, such as L. E. O. Charlton's The Next War (1937), that I missed in an earlier Abebooks order a few months ago. I already have a decent pre-WWI collection, but I splashed out on R. P. Hearne's Aerial Warfare (1909), an early and important work (a bit of a luxury as the State Library has it -- but I found a surprisingly cheap copy so I couldn't resist!)
Also I've ordered some of the more important secondary sources for my area - not least so I don't have to keep constantly renewing or re-borrowing them from the library over the next three years! These include Malcolm Smith's British Air Strategy between the Wars, and David Edgerton's England and the Aeroplane. Finally, to add a comparative dimension, I picked up Peter Fritzsche's A Nation of Flyers and Joseph Corn's The Winged Gospel, classics on airmindedness in Germany and the USA respectively.
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