Sorry I can't help you find the book - but I read it over 20 years ago. I had almost entirely lost my Christian faith by that point - but I was almost afraid of learning about the origins of the old testament.
Sorry, that was in reply to Nelson's suggestion of 'Who Wrote the Bible?'.
For the New Testament, I would suggest E.P. Sanders "Historical Figure of Jesus". It has a slight bias, but nothing too big. For more controversial but interesting historical information on Jesus and his life I'd suggest:
It's in German but there might be an English version, not sure. I've wrote a piece on "historical Jesus" myself, you can google it for "The Atheist New Testament", but it's just a "secular theory" of how Christian beliefs came to existence.