====== Merge PDF Files ======
===== pdftk =====
<code>
Join in1.pdf and in2.pdf into a new PDF, out1.pdf
  pdftk in1.pdf in2.pdf cat output out1.pdf
  or (using handles):
  pdftk A=in1.pdf B=in2.pdf cat A B output out1.pdf
  or (using wildcards):
  pdftk *.pdf cat output combined.pdf
</code>

===== Adobe Acrobat 6 =====
  * File -> Create PDF -> From Multiple Files...
  * in Acrobat 6, there is a problem with the default order of merging documents and it almost always requires user intervention to put the pages in proper order before completing the merge