Any of the Martin Gilbert ones spring to mind, great reads but some of them are a lengthy tome.
Turing byB. Jack Copeland
An interesting read about Turing's early life and his involvement with wartime codes and Bletchley Park. Also covers his contribution to the UK being the first to build an electronic computer and also the first to build a general purpose computer using a stored program. Also includes chapters on AI and the Turing test. Finally ends with details about his death and the hurried manner of the inquest into it.
I've read this too - I was interested in what was the greatest ever tank battle.
Some others:
Scram! - Harry Benson
(Helicopter operations during the Falklands War including a Wessex used as a gunship.)
St Nazaire Raid: Operation Chariot - James Dorrian
(The greatest raid of all time, an old battleship used to ram a French dry dock and knock it out of action)
Turning The Tide: Decisive Battles Of The Second World War
Nigel Cawthorne
(Various battles obviously)
The Battle of North Cape: The Death Ride of the Scharnhorst
Angus Konstam
(Bought after visiting HMS Belfast)
The Third Reich: A Chronicle
Richard Overy
Bismarck
Niklas Zetterling
Target Tirpitz
Patrick Bishop
Stuka Pilot
Hans Ulrich Rudel
(Best Stuka pilot ever and also a Nazi)
The End: Hitlers Germany
Ian Kershaw
Norman Longmate has written some excellent books about WW2, from a UK point of view: "If Britain Had Fallen" (more of a "what if") and "How We Lived Then", which is about life on the home front.
Juliet Gardiner's "The Blitz" is also very good.
Max Hastings is very readable.I have read Bomber Command, Overlord and Finest Years on WWII so far, and there are others on my list.
I am going to recommend 617 Squadron: Dambusters at War by Tom Bennett.The author was a nav in 617 squadron.I really wish i could find my signed copy of the book though.
I'd recommend all these Ben Macintyre books ...
Agent Zigzag: The True Wartime Story of Eddie Chapman: Lover, Betrayer, Hero, Spy. London: Bloomsbury Publishing, 2007. ISBN 978-0-7475-8794-1.Operation Mincemeat: The True Spy Story that Changed the Course of World War II. London: Bloomsbury Publishing, 2010. ISBN 978-0-7475-9868-8.Double Cross: The True Story of the D-Day Spies. London: Bloomsbury Publishing, 2012. ISBN 978-1-4088-1990-6.A Spy Among Friends: Kim Philby and the Great Betrayal. London: Bloomsbury Publishing, 2014. ISBN 978-1408851722.
Quite simply the best all-encompassing overview of the conflict is Max Hasting's All Hell Let Loose. It is a superb introduction and a disarming read.
Beyond that I echo comments about Anthony Beever being a superb authority on the subject and I recently read his, Max Hasting's and Stephen Ambrose's accounts of the Battle for Normandy during my two week D Day 70 tour of Northern France - it was superb.
PANTHER Germany's Quest for Combat Dominance - Michael & Gladys Green
My initial impression (from the cover only) was that this was just going to be a coffee table book of photographs. well, was I mistaken! I was staggered (and still remain so) with the depth of info and quality of photos showing all aspects of design manufacture and action seen. Also packed with info on armour effectiveness and of the effectiveness of various armour-piercing rounds on it. Thankfully, the chaps involved in my second read played their part in interupting regular supplies to the Panzer armies.
Dam Busters - James Holland. Just the book the OP @johnny70 was asking for! A very interesting read detailing the development and testing of the weapon, training of the crews and eventual mission. Also excellent insight into the organisation of the British military and manufacturing organisations as they geared up for Total War. Will read again!
As a footnote, I've visited the Eder dam many times and visited the Dambusters museum near by. There's also a recovered dummy Upkeep (the mine) at Dover castle.