A method for identifying and/or recovering at least one genetically encoded affinity reagent specific for a target molecule, the method comprising: (a) providing a molecular display system which displays a library of potential genetically encoded affinity reagents, wherein the molecular display system is phage display, wherein the library is a library of antibodies or antigen binding fragments thereof having CDR-H3 sequences identified as: R Z Z Z Z Z Z Z A/G F/I/L/M D, wherein Z Z Z Z Z Z Z is a loop of varying length composed of 25% Y, 20% S, 20% G, 10% A and 5% each of F, W, H, P, V; and wherein the CDR-H3 length is varied between 5 to 22 residues, and CDR-L3 sequences identified as: Z Z Z Z P/LI/L wherein Z Z Z Z is a loop of varying length composed of 25% Y, 20% S, 20% G, 10% A and 5% each of F, W, H, P, V; and wherein the CDR-L3 length is varied between 8 to 12 residues; (b) providing a first cell population comprising cells that express the target molecule; (c) providing a second population comprising cells that have reduced expression, no expression, or condition-specific expression of the target molecule; (d) screening the library against the first and second cell populations to obtain positive selection affinity reagents and negative selection affinity reagents, preferably with multiple rounds of selection; (e) sequencing genetically encoded affinity reagents in each of the positive and negative selection antibody affinity reagent groups, wherein the sequencing comprises deep/high-throughput sequencing; (f) identifying at least one sequence that is more abundant in the positive selection affinity reagent group as compared to the negative selection affinity reagent group; and (g) recovering at least one clone corresponding to the sequence. (a) providing a molecular display system which displays a library of potential genetically encoded affinity reagents, wherein the molecular display system is phage display, wherein the library is a library of antibodies or antigen binding fragments thereof having CDR-H3 sequences identified as: R Z Z Z Z Z Z Z A/G F/I/L/M D, wherein Z Z Z Z Z Z Z is a loop of varying length composed of 25% Y, 20% S, 20% G, 10% A and 5% each of F, W, H, P, V; and wherein the CDR-H3 length is varied between 5 to 22 residues, and CDR-L3 sequences identified as: Z Z Z Z P/LI/L wherein Z Z Z Z is a loop of varying length composed of 25% Y, 20% S, 20% G, 10% A and 5% each of F, W, H, P, V; and wherein the CDR-L3 length is varied between 8 to 12 residues; (b) providing a first cell population comprising cells that express the target molecule; (c) providing a second population comprising cells that have reduced expression, no expression, or condition-specific expression of the target molecule; (d) screening the library against the first and second cell populations to obtain positive selection affinity reagents and negative selection affinity reagents, preferably with multiple rounds of selection; (e) sequencing genetically encoded affinity reagents in each of the positive and negative selection antibody affinity reagent groups, wherein the sequencing comprises deep/high-throughput sequencing; (f) identifying at least one sequence that is more abundant in the positive selection affinity reagent group as compared to the negative selection affinity reagent group; and (g) recovering at least one clone corresponding to the sequence. <EOS>