  The nearly continuous stream of miniature comets dominated by the Kreutz
sungrazers has been an unexpected bonanza for cometary science initiated by the
launch of the Solar and Heliospheric Observatory (SOHO) in 1995. Over the
nearly 30 years since the time, no serious attempt has been made to formulate a
self-consistent model for the formation and evolution of this stream of Kreutz
comets -- the goal of the present two-part investigation. Part I describes
historical highlights of the research that has been relevant to the problem of
SOHO sungrazers (including the major contributions by Hubbard, Kreutz, and
Marsden) and furnishes preliminaries of diagnostic value that are intended to
facilitate, and provide critical information for, the work in Part II. Formerly
noted issues, such as the high frequency of close pairs in the SOHO database,
are proposed to be products of a broader process of swarming, seen in both the
nodal longitude and time. I present examples of tight swarms revealed by high
arrival rates of the SOHO Kreutz sungrazers, primarily from Population I.
