In my opinion, it is necessary to split books into two groups (at least):

CAGD - Computer aided geometric design. This category covers geometric basics, types of curves and surfaces.

1) the NURBS Book (Les Piegl, Wayne Tiller) - the comprehensive description of the B-Splines, the main type of free-form surfaces in CAD field.

2) Curves and surfaces for CAGD (Gerald Farin) - this book contains various types of geometric objects which can be used in CAD.

CAD - Computer-aided design. This section covers boundary representation schemes, design paradigms, and implementation hints.

1) Introduction to solid modeling (Martti Mantyla) - good book for a newcomer. It contains an explanation why we use solid modeling, comparison with other modeling techniques, requirements to the modeling process.

2) Solid modeling and CAD Systems - how to survive a CAD System (Ian Stroud, Hidelgarde Nagy) - modeling algorithms and data structures, Data exchange in CAD world, assemblies

3) Boundary Representation modeling techniques (Ian Stroud) - the same to above.

4) Parametric and Feature-based CAD/CAM: Concepts, techniques, and applications (Jami J Shah, Martti Mantyla) - this book is devoted to the parametric modeling using "feature" concept. As far as I know, FreeCAD utilizes this approach for modeling.

I can expand this list if needed