  We consider the Standard Model, including a light scalar boson $h$, as an
effective theory at the weak scale $v=246\,{\rm GeV}$ of some unknown dynamics
of electroweak symmetry breaking. This dynamics may be strong, with $h$
emerging as a pseudo-Goldstone boson. The symmetry breaking scale $\Lambda$ is
taken to be at $4\pi v$ or above. We review the leading-order Lagrangian within
this framework, which is nonrenormalizable in general. A chiral Lagrangian can
then be constructed based on a loop expansion. A systematic power counting is
derived and used to identify the classes of counterterms that appear at one
loop order. With this result the complete Lagrangian is constructed at
next-to-leading order, ${\cal O}(v^2/\Lambda^2)$. This Lagrangian is the most
general effective description of the Standard Model containing a light scalar
boson, in general with strong dynamics of electroweak symmetry breaking.
Scenarios such as the SILH ansatz or the dimension-6 Lagrangian of a linearly
realized Higgs sector can be recovered as special cases.
