Shadows of Forgotten Ancestors

"I think this is Carl Sagan's best book (he also thought it was his best book). It is so well-researched, so thorough, so informational, yet so readable. This book is a must for anyone interested in human evolution, human behavior (especially as it applies to all our living cousins), and the how and why we got here and they way we are)..."
~ Written on 2008-08-10

"I read this as a teenager when it first came out, and am in the middle of giving it another read. I was worried that it would be outdated information, but it really covers the subject well and any new information just compliments what this book is saying. I recommend it highly to anyone who is curious of our origins."
~ Written on 2007-12-24

"It seems unlikely that any reader of these words can be unfamiliar with Carl Sagan's extensive body of work. He was virtually without peer as a popularizer of scientific thought in our era. His public television presence as a highbrow Mr. Wizard, will be in re-runs long into the future. CONTACT, the movie version of his novel concerning a future link to other intelligences has given his thinking a pop-cultural spin. Less visible to the lay public is his brilliant scientific career, with expertise in biology and astronomy that made him a key player in NASA's Mariner, Viking and Voyager space missions -- searching for evidence of life out there. This volume is just one more piece of his puzzle, and a wonderful one. Writing with Ann Druyan, who also co-wrote the Cosmos television series, Sagan here explores the story of our beginnings. From life's emergence the authors trace the threads of chemistry and biology that have come together as the human species. The emphasis is everywhere on transition -- the constancy of change. Numerous chapters conclude with boxed quotes labelled "On Impermanence," eloquent reminders of that theme. We are too short-lived and too little informed of our parentage beyond a few or several generations back to be much more than orphans in a basket on the planet's doorstep, the authors posit. This is their exploration for roots. Intriguing hints fly in from the past. Testosterone, androgen and estrogen have the same effects on birds, ants, lizards, mice and men and women. Old, old hormones, cooked up by DNA way back where all our family trees unite. Dominance and submission are the tools of social organization in chickens, komodo dragons and elk. A little xenophobia is good for genetic diversity, but too much brings failure due to incest, so the mating of occasional Romeos and Juliets is excellent for both family's gene pools. Over-specialization is every bit as hazardous as over-generalization in the game of survival. If you are too perfectly suited to your niche your kind can be wiped out by small changes -- if you are too widely adaptable you may never find a niche in which to prosper. Yin and Yang. SHADOWS contains the clearest explanation I have encountered of why and how evolution works its relentless magic. (This book should be required reading for members of the Kansas School Board. Assumption of literacy on their part is just a wild guess -- maybe a hireling could read it aloud at their meetings?) A short summation will suffer from brevity, but here goes: The genetic codes which control development are incredibly long sequences composed of just four different molecular building blocks which are read-off in groups of three. It is the order of the molecules that creates the message (just as in our language where the orderly arrangement of any of 26 letters creates meaningful words.) Only a small portion of the genetic information in a cell is actually used; a lot of it is ignored (again due to parts of the message which say "read this" or "ignore this.") Mutations involve accidental re-ordering of the letters, and again, as in language, most produce nonsense words. Mutations in "read this" sections usually result in failure of an organism but very occasionally make it more fit for survival and the improvement is passed on. Mutations in the "ignore this" sections can persist for generations without harm until a mutation in the instruction to "read this" occurs. Suddenly new possibilities are made available (rediscovery of an ancient text), again with some successful and many failing. This results in what is now called "punctuated equilibrium" which suggests that evolution occurs in fits and starts, triggered most often by large scale environmental change and modification of the "read this" instruction set. Okay, I tried. Read the book. Excellent. Far deeper and lots wider than I can adequately describe in a brief review."
~ Written on 2007-11-27

"Perhaps no author has assumed the daunting task of explaining all and performed it as well as Carl Sagan. His plain, non-jargonistic language and penchant for organization make this book a convincing exposition of the nature of the universe, and of us."
~ Written on 2007-11-02

" This is the most readable scientific book I have read in many years.
And what a subject:Taking on the history of life and making it a page turner! Truly a work of great intellect, art and love. Would that more scientists had the ability to communicate as Carl Sagan and Ann Druyen do in this amazing book. "
~ Written on 2007-05-10