\section{Conclusion}
\label{sec:conc}

We have made a new measurement of the top quark mass,
\begin{eqnarray}
&\gevcc{\measAStatJESSyst{173.5}{3.7}{3.6}{1.5}}&\\ \nonumber
&=\gevcc{\measAErr{173.5}{4.0}{3.9}},&
\end{eqnarray} 
using a novel technique that utilizes the jet energy scale information
provided by the hadronically decaying $W$\ boson in the top quark 
events.  This provides the most precise single constraint on this 
important physical parameter.
We have performed a cross-check of this result using a more traditional
fit that does not use the {\it in situ}\ jet energy 
scale information, and found excellent agreement:
\gevcc{\measAStatSyst{173.2}{2.9}{2.8}{3.4}}.
Finally, by adding an additional algorithm to identify $b$ jets,
we achieve a small improvement in the traditional \mtop-only measurement:
\gevcc{\measAStatSyst{173.0}{2.9}{2.8}{3.3}}.

This measurement is part of a rich top physics program at CDF.
As the luminosity acquired increases from the current \invpb{318}
to an expected 4000--7000 $\invpbnoarg$ for \runii, the statistical
uncertainty on the top quark mass will improve.
Using our technique, the dominant systematic uncertainty will also
be reduced with more data.
As we approach total uncertainties of approximately \gevcc{2.0},
the uncertainties on initial and final state radiation, as well as
bottom quark jet energy scale, become comparable to the statistical 
uncertainties associated with the top quark mass and jet energy scale
measurement.
We expect that these other systematics can also be improved with more
work and more data in the relevant control samples.
Additional top quark mass results from CDF are expected in the near future.
We expect that these will continue to provide important inputs into our understanding
of the fundamental fermions and the nature of the electroweak interaction.

\begin{acknowledgments}
We thank the Fermilab staff and the technical staffs of the participating institutions for their vital contributions. This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Culture, Sports, Science and Technology of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; the Swiss National Science Foundation; the A.P. Sloan Foundation; the Bundesministerium f\"ur Bildung und Forschung, Germany; the Korean Science and Engineering Foundation and the Korean Research Foundation; the Particle Physics and Astronomy Research Council and the Royal Society, UK; the Russian Foundation for Basic Research; the Comisi\'on Interministerial de Ciencia y Tecnolog\'{\i}a, Spain; in part by the European Community's Human Potential Programme under contract HPRN-CT-2002-00292; and the Academy of Finland.
\end{acknowledgments}
