This is the first book on statistics I read from cover to cover! :-)
I have serious doubts it can serve as a textbook, and I would be really surprised if someone without any knowledge of statistics could really learn it from this book. Gonick&Smith‘s book is a great source of entertainment for those who love cartoons – the cartoonist is the first author for a good reason – and love statistics, and, therefore, know it already at some level. I would definitely recommend it to both beginners (as a complementary text for keeping motivation) and to professionals (as, for instance, a perfect in-flight reading).
There is just one tiny thing I am not comfortable with: throughout the book authors maintain the idea that it is ok to be afraid of mathematics. I completely understand why they do this, yet I feel this is a wrong message. To me, to be afraid of mathematics is the same as to be afraid of dogs. Yes, indeed, a dog bite in childhood may develop a life-long phobia of dogs. Similarly, a bad first math teacher may cause a “math allergy” for the rest of life. However, it is not good to be scared of either. Both mathematics and dogs are our friends. Big friends, indeed!