Bertha Laidler, daughter of Thomas Percival (Percy) Laidler and Christiane Alicia nee Goss was born into a socialist family. They lived above Will Andrade's bookshop in Bourke Street, Melbourne. She attended the Queensberry Street State school, Carlton.
Educated in Communism and Socialism from an early age, Laidler attended Stotts Business College and later worked for the Victorian Public Service in the Motor Registration Branch. She travelled to London in 1931 where she joined the Communist Party of Great Britain. On her return to Australia in 1933 she was active in the Communist Party of Australia, and the Shop Assistants' Union of Victoria. She later worked for the Federated Ironworkers Association of Australia in Melbourne, Sydney and Newcastle before travelling to New Zealand with fellow communists Judah Waten and Noel Counihan.
She served with the Women's Auxiliary Australian Air Force form May 1945 until May 1946. She moved to Darwin in October 1946 and met her future husband, Joseph Walker.
She curtailed her involvement with the CPA after having children.
She was a founding member of the Australian Society for the Study of Labour History.
Her publications include: How to defeat conscription and Solidarity forever.

Sources used to compile this entry: Hudson, David, 'Walker, Bertha May (1912 - 1975)', in Australian Dictionary of Biography Online, Australian National University, 2006, http://www.adb.online.anu.edu.au/biogs/A160556b.htm.