A good book for history of biology/biotechnology for lay people
Some that just come to mind, in random order:

One cannot skip reading:  


Richard Dawkins - The selfish gene


And, obviously:  


Charles Darwin - The Origin of Species


And, for those interested in the evolution of the brain (and its quirks):  


David J Linden - The Accidental Mind
Oliver Sacks - The Man Who Mistook His Wife for a Hat




Not very DNA/evolution-oriented, but wonderful science books nonetheless:


Primo Levi - The Periodic table
And the neveraging must-read:
Isaac Asimov - A Short History of Chemistry