<p>In C# are the nullable primitive types (i.e. <code>bool?</code>) just aliases for their corresponding <code>Nullable&lt;T&gt;</code> type or is there a difference between the two?</p>

A
```
Nullable<T>
```
is a structure consisting of a T and a bit flag indicating whether or not the T is valid.  A
```
Nullable<bool>
```
has three possible values: true, false and null.
Edit:
Ah, I missed the fact that the question mark after "bool" was actually part of the type name and not an indicator that you were asking a question :).  The answer to your question, then, is "yes, the C#
```
bool?
```
is just an alias for
```
Nullable<bool>
```
".