Recent results concerning the semiclassical influence of bifurcating classical periodic orbits on quantum fluctuation statistics are reviewed. These point to the appearance of a new class of universal scaling exponents that characterize the divergence of spectral and wavefunction statistics in systems where chaotic and regular dynamics coexist (i.e. in systems with a mixed phase space) in the limit as → 0.According to a conjecture of Berry (Berry 1977), statistical fluctuations on the scale of the de Broglie wavelength in the quantum wavefunctions of classically chaotic systems can be modeled in the semiclassical limit by those of gaussian random functions (e.g. random superpositions of plane waves). This in turn prompts the conjecture that spectral statistics on the scale of the mean level spacing should, in generic chaotic systems, coincide with those of the eigenvalues of random matrices (Bohigas et al. 1983).On scales larger than a de Broglie wavelength, wavefunctions can be scarred by classical periodic orbits (Heller 1984, Kaplan 1999. According to a theory developed by Bogomolny (Bogomolny 1988) and Berry (Berry 1989), in completely chaotic systems with two degrees of freedom, where all of the periodic orbits are isolated and unstable, these scars have a width of the order of 1/2 , and, in the square of the modulus of the wavefunctions, an amplitude also of the order of 1/2 . It follows from the Gutzwiller trace formula (Gutzwiller 1971), which relates the quantum density of states of a system to a sum over its classical periodic orbits, that the periodic orbits also strongly influence spectral statistics on scales larger than the mean level spacing in the semiclassical limit (Berry 1985).The question arises as to what happens when, as one changes system parameters, periodic orbits bifurcate; that is when combinations of stable and unstable orbits collide and transmute, or annihilate. Such phenomena are characteristic of dynamics in systems with a mixed phase space, where both regular and chaotic motion occurs. The contribution from a periodic orbit to the Gutzwiller trace formula and to the Bogomolny scar formula diverges when the orbit bifurcates, hinting that bifurcations are likely to give rise to fundamentally new behaviour in quantum fluctuation statistics in the semiclassical limit.That individual orbit bifurcations can have an important and sometimes dominant influence on spectral statistics was first demonstrated by Berry et al. (1998). Let N (E) denote the spectral counting function (i.e. the number of energy levels E n < E) and letN (E) = N (E) denote the local average of N over an