You can get all book MARC records from the Metadata Downloader via a public API.
Format:
metadata.springernature.com/api/metadata?eisbn=<eISBN>&format=MARCxml
Example:
https://metadata.springernature.com/api/metadata?eisbn=978-3-030-54602-1&format=MARCxml
The eISBN attribute is sometimes called Online ISBN. We only support MARC XML records, not MARC21 records.