Modifiers

Surface 
This is a modifier used in spline modelling. It will encase a spline cage and produce smooth geometry. It will only be visible if the sections of the cage are intact so ensure that all vertices are welded together. See HERE for .vtm

Hair & Fur
This is a modifier that creates hair on an object. It is calculated at the point of render. Tools allow the user to style, colour, cut, thicken, frizz etc. Warning – it does increase render times!

FFD (Freeform Deformations)
These modifiers allow the deformation of an object by creating a lattice cage around it. Control points are manipulated to change the shape of the geometry. Wonderfully animateable!

Cloth
This simple modifier allows geometry or parts of geometry to take on the attributes of cloth including collisions. It reacts well to gravity & wind etc and although highly customisable, multiple presets do nicely. Warning – this can be very buggy! Some actions need doing more than once!

MCloth
This is a dynamic version of the cloth modifier and is much better to use. It has a faster solver than cloth

Meshsmooth
This is a means of subdivision of geometry in low multiples of iterations. It applies a single smoothing group to all faces in in the object, giving the effect of rounding corners and filing edges. Warning – it can produce high poly models VERY quickly!

Turbosmooth
This is similar to Meshsmooth but is considerably faster and more memory efficient. It differs to Meshsmooth by having an Explicit Normals option. This allows Turbosmooth to compute the normals for rendering, producing a higher quality render in a quicker time. This option only works if Turbosmooth is top of the stack!

Shell
This is a modifier that gives an object a thickness (an inside & an outside).

Unwrap UVW
This is a modifier that allows the user to  assign texture co-ordinates to objects. It lets the user edit the co-ordinates by hand in a self contained UVW mapping editor