The Revelation (Animorphs, No. 45)

This book starts up a ten-book story arc that could see the end of the war against the Yeerks and the salvation of the Earth. But... that's not happening just yet. Instead, we see quite a bit in the way of changes in this book. Marco's dad is an engineer and his company is working on developing Z-space technology. The Yeerks decide that Marco's dad will have to be infested, and Marco can't bear the thought of losing another parent. So he breaks all the rules he sets for himself and tells his dad about everything. The invasion of Earth. How Marco got involved in the war. Everything. Now Marco and his dad have been targeted for temination by the Yeerks. They fake their deaths and go into hiding. But the development by humans of Z-space