The University of Connecticut Libraries has cancelled Books in Print Online.
So what do you do now if you were a regular user?....................
If you know the publisher of the book, you can get a fairly good idea from the publishers website if the title is still in print, in stock and being sold.
Worldcat can also give you subject searching capability for published titles, then go to the publishers website for in print and sale information.
For forthcoming titles, records known as CIP (cataloging in publication) records are deposited into Worldcat before publication by a publisher and/or bookseller -- then to get a date of publication and pricing, go to the publishers website.
This is a little more searching leg work to get the same information that BIP provided in one place, but it is certainly doable.
Amazon can be used as a last resort for purchase availability, but because of the unreliability of purchase price -- either new or used, Amazon is pretty chaotic for determining if a title is actually out of print at the publisher.