Which preposition to use with introductory

to Occurrences 24%

I will not attempt to describe the delight of his mother, the triumph of Willie, or the gratification of his father, who saw in this good promise of his boy's capacity; for all that I have written hitherto is only introductory to my story, and I long to begin and tell it you in a regular straightforward fashion.

in Occurrences 1%

As the necessity for a Geography more introductory in its character than those now in use has been long felt, the Author would respectfully solicit the notice of his fellow-teachers to this little work.

of Occurrences 1%

At length, however, though the class of the winter, all told, amounted to less than a hundred, a sufficient number had arrived to induce the professors to commence their lectures; and the introductory of Dr. Rush was a performance of deep and touching interest, and never, I think, to be forgotten (while his memory endures), by any one who listened to it, and was susceptible of the impression it was calculated to make.

Which preposition to use with  introductory