I recently finished Margaret MacMillan's World War I history book The War that Ended Peace as recommended by David over at duffandnonsense. It covers the people and events leading up to the war rather than the war itself.
I bought the Kindle version so the maps aren't as useful as they would be in a traditional book, but unless your geography is even worse than mine it should not cause too many problems.
I'm not a great history buff but the book is an excellent read. Very well written, it takes the reader through the myriad causes of the Great War. No doubt people from my generation all have some familiarity with the main events, but MacMillan's book brings them together in an extremely readable way.
I'll finish with this quote from the blurb which neatly sums it up, although if you read the book you may have some reservations about the word intelligent.
The story of how intelligent, well-meaning leaders guided their nations into catastrophe. Immersed in intrigue, enlivened by fascinating stories, and made compelling by the author's own insights, this is one of the finest books I have read on the causes of World War I (Madeleine Albright, former Secretary of State)