The Schengen Agreement states that any U.S. citizen entering The Netherlands for up to 90 days must have a valid passport and does not need to obtain a visa.
If you are looking to stay more than 90 days you must apply for a visa through the Embassy of the Netherlands.
A valid passport from your native country is necessary to travel to most countries. You can apply for one online or at your local post office.
Since 2004 Dutch government suggests travelers be aware of news coming out of The Netherlands after terrorist problems.
The Netherlands has a low crime rate, but it is important for tourists to keep money and electronic devices hidden at all times. Also be aware of pick-pockets.
No shots are required to travel to The Netherlands, but it is suggested you visit your doctor before to obtain copies of generic prescriptions and to check your overall health.