Books and book chapter metrics can assist in measuring the reach and impact of scholarly publishing. They can be more difficult to find than article and/or journal metrics, as Scopus and Web of Science are not comprehensive in their coverage and don't consistently index book chapters.
Book reviews can provide evidence of the esteem in which your publication is held by others in the discipline area. Library holdings may give an indication of the reach of your publication, and demonstrate that it is considered useful for teaching and research purposes.
These metrics may be useful for promotion, employment and grant applications.
For citations
Book Citation Index (Web of Science)
For library holdings
Other measures of impact you could consider