thats a good book to pass the test. i used that book.
but if you wanna truly understand the hardware, i recommend also this book by scott mueller.
i read the 14th edition, but the 15th edition is out now.
upgrading and repairing pcs , its a chunky book , but it goes through hardware like you wouldn't believe. this book will make you a hardware guru, like me. =)
for network+, im also david groth network study guide to pass the test. but reading upgrading and repairing networks 4th edition, good hardcore stuff.