  This review summarizes papers which analyze impact of self-citation on
research evaluation. We introduce a generalized definition of self-citation and
its variants: author, institutional, country, journal, discipline, publisher
self-citation. Formulae of the basic self-citation measures are given, namely
self-citing and self-cited rates. World literature on author, institutional,
country and journal self-citation is studied in more detail. Current views on
the role and impact of self-citation are compiled and analyzed. It is found
that there is a general consensus on some points: (a) pathological is as
excessive self-citation so its total absence; (b) self-citation has low impact
on large science units but may be critical for analysis of individual
researchers; (c) share of self-citations is generally higher for units with low
bibliometric performance, while top scientists, institutions, journals receive
the majority of their citations from outside. This review also considers how
bibliometric instruments and databases respond to challenge of possible
manipulation by self-citations and how they correct bibliometric indicators
calculated by them. The first part of the review presented here deals with the
fundamental terms and definitions, and the most discussed and studied type of
the self-citation, author self-citation. The paper was funded by RFBR, project
number 20-111-50209
