I will be taking about recent new developments in the secular
hierarchical three body approximation
and will mention a few applications.

The search for extra-solar planets has led to the surprising discovery
of many Jupiter-like planets in very close proximity to their host
star, the so-called ``hot Jupiters'' (HJs). Even more surprising, many
of these HJs have orbits that are eccentric or highly inclined with
respect to the equator of the star, and some (about 25%) even orbiting
counter to the spin direction of the star. This poses a unique
challenge to all planet formation models. We show that secular
interactions between Jupiter-like planet and another perturber in the
system can easily produce retrograde HJ orbits. We show that in the
frame of work of secular hierarchical triple system (the so-called
Kozai mechanism) the inner orbit's angular momentum component parallel
to the total angular momentum (i.e., the z-component of the inner
orbit angular momentum) need not be constant. In fact, it can even
change sign, leading to a retrograde orbit. A brief excursion to very
high eccentricity during the chaotic evolution of the inner orbit
allows planet- star tidal interactions to rapidly circularize that
orbit, decoupling the planets and forming a retrograde hot Jupiter.
We estimate the relative frequencies of retrograde orbits and counter to
the stellar spin orbits and find that the they are consistent with the
observations.