We present a paradigm for developing arbitrarily high order, linear, unconditionally energy stable numerical algorithms for gradient flow models. We apply the energy quadratization (EQ) technique to reformulate the general gradient flow model into an equivalent gradient flow model with a quadratic free energy and a modified mobility. Given solutions up to t n = n∆t with ∆t the time step size, we linearize the EQ-reformulated gradient flow model in (t n , t n+1 ] by extrapolation. Then we employ an algebraically stable Runge-Kutta method to discretize the linearized model in (t n , t n+1 ]. Then we use the Fourier pseudo-spectral method for the spatial discretization to match the order of accuracy in time. The resulting fully discrete scheme is linear, unconditionally energy stable, uniquely solvable, and may reach arbitrarily high order. Furthermore, we present a family of linear schemes based on predictioncorrection methods to complement the new linear schemes. Some benchmark numerical examples are given to demonstrate the accuracy and efficiency of the schemes.solutions [13]. This is because non-energy-stable schemes may introduce truncation errors that destroy the physical law numerically. Thus, developing energy stable numerical algorithms is necessary for accurately resolving the dynamics of gradient flow models [20,21,23,30,44].Over the years, the development of numerical algorithms has been done primarily on a specific gradient flow model, exploiting its specific mathematical properties and structures. The noticeable ones include the Allen-Cahn and Cahn-Hilliard equation [1,9,11,20,24,32,36,42] as well as the molecular beam epitaxy model [6,12,[26][27][28]41]. As a result, most numerical algorithms developed for a specific gradient flow model can hardly be applied to another gradient flow model with a different free energy and mobility. The statusquo did not change until the energy quaratization (EQ) approach was introduced a few years ago [39,44], which turns out to be rather general so that it can be readily applied to general gradient flow models with no restrictions on the specific form of the mobility and free energy [16,40] (so long as it is bounded below, which is usually the case). Based on the idea of EQ, the scalar auxiliary variable (SAV) approach was introduced later [31], where each time step only linear systems with constant coefficients need to be solved. Several other extensions of EQ and SAV approaches have been explored further. For instance, regularization terms [5] and stabilization terms [38] are added, and the modified energy quadratization technique [22,25] are introduced to improve the EQ methodology. We notice that most existing schemes related to the EQ methodology are up to 2nd order accurate in time. Some higher-order ETD schemes have been introduced to solve the MBE model and Cahn-Hilliard models recently, but their theoretical proofs of energy stability are still missing. Shen et al.[30] remarked on higher-order BDF schemes using the SAV approach, but no rigorous theoretical p...