Actually this quote was not said by famed futurist Alvin Toffler, but
Samuel Johnson (1709-1784), in 1775.
The full quote, according to SamuelJohnson.com is:
"Knowledge is of two kinds. We know a subject ourselves, or we know
where we can find information upon it. When we enquire into any
subject, the first thing we have to do is to know what books have
treated of it. This leads us to look at catalogues, and at the backs
of books in libraries."
Samuel Johnson (Boswell's Life of Johnson)
The source given is:
"On April 18, 1775, Boswell, Johnson, and Sir Joshua Reynolds were
visiting Richard Owen Cambridge, whose villa contained both an
impressive art collection and an extensive library. After a quick
introduction to Cambridge, Johnson ran to the library to inspect its
contents. Johnson's line above came in response to Cambridge's
questioning him regarding the intensity of his interest in the
contents of the library, that he would spend such time examining the
books on the shelves."
Knowledge is of Two Kinds: Samuel Johnson
Here is the excerpt from the book mentioned above, Boswell's Life of
"No sooner had we made our bow to Mr. Cambridge, in his library, than
Johnson ran eagerly to one side of the room, intent on poring over the
backs of the books. Sir Joshua observed, (aside,) He runs to the
books, as I do to the pictures: but I have the advantage. I can see
much more of the pictures than he can of the books. Mr. Cambridge,
upon this, politely said, Dr. Johnson, I am going, with your pardon,
to accuse myself, for I have the same custom which I perceive you
have. But it seems odd that one should have such a desire to look at
the backs of books. Johnson, ever ready for contest, instantly
started from his reverie, wheeled about, and answered, Sir, the
reason is very plain. Knowledge is of two kinds. We know a subject
ourselves, or we know where we can find information upon it. When we
enquire into any subject, the first thing we have to do is to know
what books have treated of it. This leads us to look at catalogues,
and the backs of books in libraries. Sir Joshua observed to me the
extraordinary promptitude with which Johnson flew upon an argument.
Yes, (said I,) he has no formal preparation, no flourishing with his
sword; he is through your body in an instant."
James Boswell's "Life of Johnson"
Here is a link to Amazon.com's page for The life of Johnson by James
I hope this helps, and please do let me know if you need any other
information before you rate my answer. Thank you!
Alvin Toffler Future Shock "knowledge is knowing" quote
Alvin Toffler knowledge quote
Alvin Toffler knowledge quote where to find out
Sam Johnson "Knowledge is of two kinds"