After years of experience at various bookselling firms, he undertook his own business as a publisher, first as J. Whitaker and later as J. Whitaker & Sons. Early publications were theological works. In January 1858 he launched
The Bookseller and in 1869 published the first issue of ''
Whitaker's Almanack'', a reference annual, which met with immediate (and lasting) success. In 1874 he launched the
Reference Catalogue of Current Literature, whose goal to "anthologiz[e] publishers' catalogues". This reference work went through numerous editions. He helped "organize and distribute relief funds for Parisian booksellers" following the
Franco-Prussian War (1870–71). ==Personal life==