I don't actually picture having to deal with this too much personally. First, because Scott and I live on an island in the middle of the Pacific Ocean, thousands of miles away from any grandmas... and Secondly, because both Scott's and my families are generally very reasonable people.
However, just as the Mama Bear hormones can turn (us) generally reasonable women into overly-protective psycho-moms, apparently it is also possible for grandparents (especially grandmas, who were, after all, Mama Bears themselves not too long ago) to become more overbearing and opinionated than necessary or desired.
This chapter was rather long because there are so many possible scenarios, depending on where you live in relation to your parents (his and hers) and how reasonable everyone is. But I'll summarize a couple of key points from the chapter that will be good to keep in mind regardless of the scenario...
1. Grandmas love love love their grandbabies. They want to hold them and cuddle them and smell them... and impart some sort of their own legacy on them as well. They hope that baby looks like their side of the family. They are sure they know how to take care of them because, afterall, they have raised at least one if not several into successful adults (ahem, you). And you know what? You slept on your tummy and were bottle fed and you turned out just fine.
2. We, as the nuclear family, do still have ultimate authority and responsibility for the lives of our little ones. This means that major decisions still lie with us, which can be a blessing and a curse. So maintain your ideals to some degree, but maybe give grandma a little slack when its her turn with the baby. Let it go if kids get to bed 30 minutes later than usual, or are allowed a snack/dessert that you normally wouldn't give them. It's wonderful when kids have a chance to bond with their grandparents so sometimes it's best to just step aside and let that happen. Hey, the more adults in their world that love them, the better.
In many cases, families get closer once little ones enter the picture. You will likely have a whole new understanding and respect for your own mom. Or you may gain a whole new appreciation for your mother-in-law if, for example, she lives close by and volunteers to watch your kids so you can take a break to get to your yoga class.
That being said, inlaws can unknowingly cause problems in lots of ways. Maybe there's too much pressure on you to spend more vacation time with one side of the family (depending on where you live this might be inevitable). Maybe you feel that his dad doesn't think about safety quite enough when your kids are around (i.e. when knives are left right out on the counter). Maybe your dad is too critical of decisions you've made regarding your choice to work outside the home. Maybe your husband thinks you and your mom make all the decisions and he's left wondering where he fits in to the picture. Maybe your mom and dad are divorced and you feel like they are competing with each other for time with your kids or who gave the best birthday gift... This list could go on and on...
Regardless of the scenario, communication with your husband is the key. Remember that your husband and kids come first (and vice versa- YOU are his priority as his wife) and then all the other relationships will fall into place. The two of you then need to sit down and hash out your priorities. Set up a schedule of who you're going to visit and when. Create your own new traditions. And remember that it is your responsibility to run interference if your side of the family is the offending party. Just like you shouldn't be the one to have to call his dad out on his lack of judgement in showing your 4 year old how to shoot a gun, your hubby shouldn't have to tell your mom to stop dropping in every Saturday morning for breakfast.
In the end, remember point number one above. Grandmas love love love their grandbabies. And that's awesome for your kids.