This talk give provide an overview concerning the main approaches of the literature concerning indexing techniques. These methods will be discussed according to their context of utilization.

The outline of the presentation will be the following

1. Introduction : challenge related to document indexing
2. Space-partitioning-based methods : KD Trees, NKD and PKD Trees, PA Trees, R Trees, R* Trees, SR Trees, X Trees
3. Clustering-based methods : K-Means Clustering Trees, Agglomerative clustering Trees, K Medoids clustering trees,
4. Hashing-based methods  : Locality Sentive Hashing,( LSH), Kernelized LSH, Entropy based LSH, Multi-probe LSH
5. Latent Semantic Indexing (LSI)
6. Main schema related to Information spotting problems : from information characterization to indexing
7. Conclusion - discussion