I had to read "Supermob: How Sidney Korshak and His Criminal Associates Became America's Hidden Power Brokers" as it was the basis of a class in a Life Long Learning program. I'm an avid reader of non-fiction and history. However, "Supermob" was perhaps one of the worst books I've ever come across. I noticed several inaccuracies in basic facts. For example, it was wrongly stated that Nancy Reagan had been married before she wed Ronald Reagan. This kind of misinformation was just randomly presented to the reader. As soon as I discovered two errors in a non-fiction work, I usually stop reading. Sadly, since it was a textbook for a class, I couldn't simply discard it, although I really wanted to.
There is a distinct difference between writing dull and dry history and a chaotic, unstructured history. Gus Russo seems to be more of a storyteller or raconteur rather than a meticulous journalist or author. He assembles interesting anecdotes but appears to fabricate his own context to craft a more engaging story. This approach undermines the credibility of the book and makes it a less reliable source of information.