Complex sentence: Mueller also has a series titled "Upgrading and Repairing Laptops" that shares some of the material of "Upgrading and Repairing PCs" but focuses on the maintenance of portable computers.
Split into simpler sentences: Mueller also has a series similar to his "Upgrading and Repairing PCs", "Upgrading and Repairing Laptops". It shares some of the same material as his PC books but focuses on the maintenance of portable computers.