 meaning:
<P></P>
<table border = "1">
<TR>
<TH> Button </TH>
<TH> Name </TH>
<TH> Go to </TH>
<TH> From 1.2.3 go to</TH>
</TR>
<TR>
<TD ALIGN="CENTER">
 [ &lt; ] </TD>
<TD ALIGN="CENTER">
Back
</TD>
<TD>
previous section in reading order
</TD>
<TD>
1.2.2
</TD>
</TR>
<TR>
<TD ALIGN="CENTER">
 [ &gt; ] </TD>
<TD ALIGN="CENTER">
Forward
</TD>
<TD>
next section in reading order
</TD>
<TD>
1.2.4
</TD>
</TR>
<TR>
<TD ALIGN="CENTER">
 [ &lt;&lt; ] </TD>
<TD ALIGN="CENTER">
FastBack
</TD>
<TD>
previous or up-and-p