If you're planning a visit to the USA you may not be aware that as from April 1st, 2016 you need a biometric passport to be allowed in.
In order to check that you have this type of passport simply look on the cover to see whether it has the gold symbol at the bottom.
US Homeland Security states:
The passport must have a machine-readable zone on the biographic page
The passport must be an electronic passport with a digital chip containing biometric information about the passport owner
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