The Case of the Backward Mule by Erle Stanley Gardner (Pan, 1957)

I got this one from a bookshop in Tasmania via eBay:

 

Chase in San Francisco's Chinatown

To baffle the lie-detector clamped on his arm, Terry Clane practises the intense concentration he learned in the Orient.  But the sight of a little Chinese figure--an old man riding backward on a mule--sends the indicator-needle leaping; for he'd given it once to Cynthia, his former fiancee and close friend of a man convicted of murder who has escaped.  Says the police examiner: "Either there's something I haven't accurately diagnosed or else ... you murdered Horace Farnsworth."  Then begins a grim game of hide-and-seek through Chinatown.

Erle Stanley Gardner--a prolific mystery writer, best known as the author of 82 (!) Perry Mason books.  None of his works could be described as great literature (not surprisingly, given his output) but they are mostly entertaining light reading.  I find them great reading for the daily commute.

The Case of the Backward Mule is one of the (many) books Gardner managed to write when he was not churning out Perry Mason mysteries.  The book has many "Chinese" elements, as you can see from the cover of this edition and the blurb.   It's interesting to note that Gardner probably drew upon his own experiences in writing this.  As a young lawyer he had many clients (and made some lifelong friends) among California's Chinese community.  Being the writer he was, you can't expect any deep insight into China or the Chinese from this book, nor is it entirely free of cliches, but it is surprisingly sympathetic and lacking in the racism of its era!