Using the pen tool you can put down eight points to make the general T shape:
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*----* *----*
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Then select the top two with the Direct Selection Tool (A) or the white arrow by clicking above and to the left of the left most point, then dragging down and to the right, until you've encompassed the right point.
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*----* *----*
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After you have those two selected go to the menu Object>Path>Average....
Then select Horizontal
This will average out the two top points, making a straight line across the top.
Do the same to the bottom, and the middle points.
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*----* *----* -- select all four of these
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For the four sides, do the same, but select "Vertical".
I don't know any good books on this, but the tutorial is pretty good, you'll learn what you need to know with it.