hxxx, no it isn't common. Neither is polygyny, though it was practiced in Biblical days and still practiced in Islam, it is basically for the rich. Most men couldn't afford more than one wife financially or emotionally.
Halfabo nope, that is not what that particular book said.
"There is even less evidence regarding female age at marriage. As noted, the overwhelming impression givin in the legal sources is that father betrothed their daughters while they were still minors. Without doubt, this happened. We do not know, however, how often it happened."
Then it goes on to talking about men checking for "blemishes" on the women and how puberty ties in with this and the Pagan Babylonian Law and marriage. Then the author gives an example of a story where a little girl small enough to sit on her grandfathers shoulders was already betrothed. The grandfather didn't like this so the author goes on to say, "Betrothal was early, but the practice of early betrothal was apparently not uncontested." page 108
It happened in the early Hebrew culture just like it continues today with Abraham's Semitic descendants, the Arabs. It was rare then, and is rare today, yet it is sanctioned by Hebrew Law through the Talmud. That is where Sharia Law comes from. Mohamed said that the other tribes didn't keep the covenant with their god, but his followers would. That is why they stone people and desecrate religions that have idols they worship, like crosses or Buddhas.