The Black Echo by Michael Connelly is the debut novel of the police detective character Harry Bosch who we have all grown to love.
Harry Bosch at this point has been demoted from the L.A Homicide squad to the lesser Beverly Hills squad.
On attending a suspicious death, he recognises the body of a fellow 'tunnel rat', on of the elite squad of soldiers whose task it was to search for Viet Cong soldiers in the burrows beneath many Vietnamese towns and cities during the Vietnam War.
He always keeps keeps meticulous 'Murder Books' - the names for the police records of the circumstances surrounding a murder - and through his own records he is able to link this death to an unsolved bank job involving breaking into the vault via tunnels.
The FBI become involved and Harry Bosch with his brilliant detective skills builds up a case and his suspicions.
This is a superb books, well-written, action packed and fast-paced, and if you have never read Michael Connelly before, this is as great an intro as any.