Oxford dictionary up on Amazon

I've noticed that my co-authored, forthcoming book - the Oxford Dictionary of Human Geography - is available for pre-order on Amazon.  It will be formally published in April 2013.  I was recently asked what the main differences are between it and the Dictionary of Human Geography published by Blackwell.  In a nutshell, our dictionary has more entries (over 2100 vs c.1000); wider coverage across the discipline; more variety in entry type (biographies, places, events, books, organisations, political agreements, in addition to concepts and methods); length of entry (more concise); level of entries (aimed at undergraduates and interested generalists rather than advanced postgrad and academics); style of entry (very clear with limited use of jargon); consistency in entries (all written by the three authors rather than an edited collection); price (£11.99 vs £24.99); its much smaller and lighter.  Whilst some might view them as competing texts, I think they're complementary, with the Blackwell dictionary having longer, more advanced entries.