Based on the information available, "Walsh Street" by Tom Noble explores the following themes and topics:
* **True Crime:** The book investigates the **murders of two policemen** in Melbourne in October 1988 【1】【2】.
* **Australian Criminal Justice System:** It details the **two-and-a-half-year investigation, trial, and subsequent acquittal** of the four men charged with the crime 【2】.
* **Melbourne's Underworld:** The book delves into Melbourne's criminal world, touching on themes of **money, power, and violence** 【3】.
* **1980s Concerns and Feelings:** The book reflects the concerns and general feeling of the 1980s 【4】.
These themes could help you draw connections to other books in a library that deal with true crime, the criminal justice system in Australia, or the history of crime in Melbourne.