The Inspector Banks you see in the BBC series is a much colder and reserved character than the more convivial and family-oriented Inspector Banks featured in the series by Peter Robinson. Both are good but I have a slight preference for the mystery novel version.
In Wednesday's Child a child is taken from her mother by two social workers. When the child is not returned, Banks discovers the individuals were not social workers but has no idea who they were and why they took the child. The mother, whose live-in boyfriend is a small-time thief is not under suspicion. Then a body of an ex-con who was savagely gutted is found in the ruins of a local foundry. There does not seem to be any connection between the two. Banks focuses on the murder victim while his boss, D.S. Gristhorpe, focuses on the abduction as it raises the ghost of a past case.
Eventually the pieces come together for an interesting and intelligent solve.
If you are looking for a good solid read that is more challenging than a cozy and focused on characters as much as the whodunit. Wednesday's Child and Peter Robinson's Inspector Banks series is an excellent bet.