How is Game of Thrones related to the books?

I didn't read A Song of Ice and Fire, but I am interested in doing so unless the series is gonna be the exact replica of the books.

Is the show taken from a certain book (i read there are 7)?

Is it starting where the books started or did it skip sections?How is Game of Thrones related to the books?
So far the TV show has been very faithful to the book.

The only major changes is the relationship between Dany Targaryen and her barbarian husband Khal Drogo: in the book, Khal Drogo is very gentle to Dany on their wedding night, and their marriage starts out as a loving one. In the TV series, Dany is fearful of Drogo in the beginning, and Drogo is very rough and cold to Dany at first; but I assume they will gradually grow to respect and love each other like in the book.

The TV series condensed parts of the book, skipped a couple unimportant chapters, and switched the order of a few chapters. Otherwise, the series has so far stayed very close to the book.How is Game of Thrones related to the books?
Game of Thrones is the first book of the series. So far, the show has been a pretty close adaptation of the book. A few scenes were simplified, some dialogue altered, but overall they've done well. Probably the biggest diversion has been that Dany and Drogo's relationship was portrayed very different on screen than it was in the books.