The Drake Equation is one of those things that when you see it you say "well, that's simple" but you would never have thought about creating it yourself.
Unfortunately most of the values you "plug in" are "guesstimates", but it does provide a foundation for discussion...
i was just browsing the other day and came across the Wikipedia page on the Drake Equation. It's really just a way to add structure to guesswork about probability of life in our galaxy. Using very optimistic estimates, we see that there are 20,000 intelleigent civilizations trying to communicate right now (although the closest may still be 350 light years away). A more pragmatic estiamte tells us that there are 2 (and one of those is us!). Depressing or inspiring?
One of the things the book talks about is the possibility of creating "Von Neumann" probes that would travel at sub-light-speeds to the nearest stars. Once they arrive they would do two things: (c) send information back to us and (b) replicate themselves using materials mined from asteroids and comets with the new probes carrying on to the next nearest stars.
This is something we should be capable of doing in the not-so-distant future. Yes, it would take a while for the probes to travel to the next star, but once this started rolling it should take only 1 million years for our probes to have visited every star in our galaxy.
The thing is that if we can do it, so could other intelligent races ... so why don't we see these probes?
This comment is probably off topic a bit, but I think would be interesting to your readers.
There is a website called Symphony of Science (http://www.symphonyofscience.com/) where a talented musician by the name of John D. Boswell has set selected video snippets of popular science personnel explaining our Universe or aspects of it. What was spoken words become sung lyrics with the help of specialty software for the purpose, and these are then set to music which he composes and then sync's to the video.
It is impressive stuff whether you believe the premise of the speaker or not.
As a closet musician, I like his music.
If you like you can get all the videos as a bundle at http://melodysheep.bandcamp.com/album/symphony-of-science-bundle-v10 free, or you can donate to the site if you like.
I would be interested in any comments about the site as well.
I haven't read the book, but I appreciate your review of it.
I definitely believe we (in our form and with our experiences) are unique in the Universe, at least until such time as we colonize all these 'earth like' planets that are being found. Whatever other intelligent life is out there will be (and has to be) different and unique in their own right, unless (as Ancient Astronaut theorists believe) our race has been visited and influenced by 'people' closely similar to us thousands of years ago.
One thing for sure: We can be wiped out very quickly by the wrong set of circumstances, and that fact alone should force us to take better care of ourselves and where and how we live and if possible plan for the continuation of the human race elsewhere if we have the time.
The vast separations between the stars and galaxies may practically limit physical interaction to only light speed optical or radio communication.
How exciting or possibly frightening it would be to find out we are not unique and actual physical interaction is possible.