After postings at Arakan, Sagaing and elsewhere, Collis was district magistrate in Rangoon in 1929-1930, a period when relations between Burmese, Indians and British became particularly difficult.
In Trials in Burma he gives special attention to the political trial of Jatindra Mohan Sengupta, mayor of Calcutta, for sedition in impromptu speeches made during a brief visit to Rangoon in 1930; also to two criminal trials which became politically charged because they brought to light underlying attitudes of British merchants and army officers to Burmese people (the same attitudes that were soon to be exposed in a fictional context in George Orwell's Burmese Days).
Collis's judgments were (according to his own analysis) too independent to be pleasing to the then British Government of Burma, arousing the particular disapproval of his superior, Booth Gravely, Commissioner of the Pegu Division.
It contains an introduction written by the author dated 14 May 1945, and commenting on events in Burma since the book was originally published.
The book was anonymously reviewed by George Orwell, who also lived in British Burma, in The Listener in 1938.