Bonet and Wood have done an excellent job with this book. After motivating what they are trying to do with simple examples of nonlinear mechanics, they move into some basic vector and tensor math. Summation signs are explicitly used, so if you are new to continuum mechanics you don't have to try to learn the ins and outs of the seemingly bizarre notation at the same time as the fundamental concepts (although you really should learn it at some point in time). Once the math is set up, Bonet and Wood move into finite kinematics, the force balance, material constitutive models, and finally, getting all of the above set up in an actual computer code (which is available for download) to do some FEA.

The strong point of the book is how patient the authors are with you. I found the derivations to be very lucid, with most, if not all, of the important steps shown. Bonet and Wood always tie things back to linearizing the nonlinear problem in anticipation for putting it on the computer. The Newton-Raphson procedure, and its various improvements (line search, etc.) are very nicely explained, so it is clear not just what and why but how we go about solving nonlinear mechanics problems. I highly recommend this book for starting to learn continuum mechanics and one way of solving its problems on the computer.

Nota bene: the emphasis is on large-deformation elasticity, which is a good, relatively simple place to start in continuum mechanics. The material models are all eventually taken as isotropic (which is more than just extra constants, as another reviewer pointed out, since then you must use the exponential map). Plasticity is briefly covered, but only the basic J2 model with hardening. Search elsewhere (Simo and Hughes, or Dunne and Petrinic) if you are interested in computational plasticity. Maybe (and hopefully) in the next edition Bonet and Wood will get to those topics.