 a consistent and reliable manner.

<p>

<a name="%_sec_Temp_4"></a>
<h3><a href="r5rs-Z-H-2.html#%_toc_%_sec_Temp_4">Background</a></h3><p>

The first description of Scheme was written in
1975&nbsp;[<a href="r5rs-Z-H-14.html#%_sec_7.3">28</a>].  A revised report&nbsp;[<a href="r5rs-Z-H-14.html#%_sec_7.3">25</a>]
 appeared in 1978, which described the evolution
of the language as its MIT implementation was upgraded to support an
innovative compiler&nbsp;[<a href="r5rs-Z-H-14.html#%_sec_7.3">26</a>].  Three 