Pax by Sara Pennypacker
This book was about a young boy named Peter who was forced to give up his pet fox Pax by releasing him back into the wild. The story dives into, not only the mental and emotional hardships it caused between both Pete and Pax, but also the physical strains and how they forced them both to be stronger. A timeless tale that is great for all ages. I do hope one day to find out whatever became of Pax, Peter and Vola.