Help-Mathematica Book-Reference Guide-Installation and Organization of System files

2D vs. 1D exparess :
e.g. x^y = (x^y)
 Noet : x y = x*y ≠ xy

t = 1Module[{t}, t = 9; t]t

tWith[{t = 5}, t + Sin[t]]t

\(m = i\^2; 
Module[{i = a}, i + m]\)Block[{i = a}, i + m]

<< DiscreteMath`ComputationalGeometry`\(data2D\  = 
      \ {{4.4, \ 14}, \ {6.7, \ 15.25}, 
\ {6.9, \ 12.8}, \ {2.1, \ 11.1}, 
        \ {9.5, \ 14.9}, 
\ {13.2, \ 11.9}, \ {10.3, \ 12.3}, 
        \ {6.8, \ 9.5}, 
\ {3.3, \ 7.7}, \ {0.6, \ 5.1}, \ {5.3, \ 2.4}, 

        \ {8.45, \ 4.7}, \ {11.5, \ 9.6}, \ {13.8, \ 7.3}, 
\ {12.9, \ 3.1}, 
        \ {11, \ 1.1}}; 
DiagramPlot[data2D]\)

$Packages

Mehematica resource library (http://library.wolfram.com/)
How do I convert my existing graphics files to data files that Mathematica can import? 
(http://support.wolfram.com/Graphics/Contour.Density/ImageDataImport.html)
Import and Export: Collaboration with Other Software (http://www.wolfram.com/products/mathematica/newin4/new_import.html)
ListConvolve: An Image Processing Example (ListConvolve: An Image Processing Example)
Raster (http://documents.wolfram.com/v4/RefGuide/RefGuide/Raster.html)
Graphics and Sound F&Q (http://support.wolfram.com/Graphics/)
Import GIF (http://support.wolfram.com/Graphics/Formats/GIF/index.html)