Whether you are fostering a cat or bringing home a new cat to meet the resident cat, you are in for some transition.
We recommend reading this website. We also recommend the books and website of Pam Johnson.
Here is a quick guide to introducing a new cat.
what to expect when adopting a new cat
Of course, we're also here to help you with your questions about adopting and integrating our cats. Beyond our volunteer core, we have a listserve with about 200 members on it, many of whom LOVE to give their two cents on various cat issues. We would be very happy to try and answer your questions! Remember, though, we are not veterinarians, and can only give our advice as "cat people," not as veterinary professionals.