What can I do to know of the contents of my father’s Will?

If there was actually a Will, it would have had to be entered into probate. At that point, any beneficiaries should have been notified of their inheritance.  If you were not notified then you may well have not been left anything.  The fact is that children have no automatic inheritance rights (under a Will). In other words they can be disinherited. If they were, as general rule the Will should contain specific language of disinheritance. That having been said, once a Will is filed, anyone can see a copy of it; it is a matter pf public record. Just go to the Probate Court in the county in which your father was domiciled at the time of his death. This is where it would have been filed.

Furthermore, you should also be aware that certain assets can be transferred outside of probate. For example, if your father had a small estate, property may have been transferred by affidavit (if applicable under state law).  Also, some assets may have been held as "joint tenants with right of survivorship", in which case the other joint tenant(s) would have received your father's share of the property by operation of law. In addition, funds in an IRA, pension, 401(k), or other retirement plan also by-pass probate and go directly to the named beneficiaries. The same holds true for any proceeds from a life insurance policy.  

Note:  If it turns out that your father died "intestate" (i.e. without a Will), then the laws of the state where he died would control. In such a case, typically an estate is divided between a surviving spouse, if any, and all of the deceased's children.

However, Will or not, even if you were to have inherited but did not there may not be anything that you can do after so long a time. You would need to speak with a probate attorney.