Complex sentence: Through his family's business, Reed became a prominent typefounder, and wrote a classic "History of the Old English Letter Foundries" which, published in 1887, was hailed as the standard work on the subject.
Split into simpler sentences: Through his family's business, Reed became a prominent typefounder, and wrote a classic "History of the Old English Letter Foundries". By then he had begun his monumental "Letter Foundries" history which, published in 1887, was hailed as the standard work on the subject.