Solution for 26 June cryptic crossword clue

He’s enthralled by zodiac sign in reference book (9)

Solution – thesaurus

This is what is known by cryptic aficionados as a container clue.  For more on different clue types see the sidebar under the StumbleUpon button.

So "he's" "enthralled by" indicates that "hes" is found within the solution.  And Taurus is a zodiac sign – it had to be a 6 letter one so that reduced the possibilities to 4.

And a "thesaurus" is a type of reference book.

T + hes +aurus = thesaurus.