If you are going to this region primarily for the wildlife then this volume is indispensable. Your ship's library is likely to have a copy, but don't bank on it and if you have your own then you can browse at leisure in your cabin rather than fighting over the reference copy. It covers not only the wildlife of the Peninsula, but also of outlying islands likely to be visited on the way such as the Falklands and South Georgia. If you are visiting for the wildlife then stretching the budget to include these two islands is a must.
Other guides are much less comprehensive and may lead to misidentification of birds in particular as not all species are included - the variety of prions and petrels is not to be underestimated !