We will first review some connections between multiple access in wireless networks and compressed sensing. Then, we present a novel divide-and-conquer compressive sensing (CS) based approach for the unsourced random access problem introduced by Polyanskiy. In the proposed scheme, each user's data is first encoded using an outer linear block code and the outer codewords are split into several sub-blocks. Each sub-block is encoded using a compressed sensing based encoder. At the receiver, the sub-blocks are decoded using compressed sensing decoder and their outputs are combined together using a low-complexity tree based algorithm. The proposed scheme outperforms existing practical coding schemes in literature and is only approximately 4.3~dB away from the Polyanskiy's achievability scheme using a random Gaussian codebook.