This chapter has reviewed the current state of crystalline silicon solar cells and modules. The main
lines defining the structure of the described situation can be summarized as: 
• Technology diversification. These two challenges are to be faced by solar cell production technology in the next years. Intensive preindustrial research is being conducted and solutions are being developed along several different lines.
• Quality. Product reliability and durability and environmental and aesthetic quality are as important as cost for the growth of PV industry, and this also influences technology.
• Long-term scenario. Alternatives to crystalline silicon technology are being thoroughly pursued, and presumably some of them will succeed in reducing photovoltaic costs to competitive ones. Nevertheless, for these so-called leapfrogs to take place, a mature PV market should consolidate, for which silicon technology is essential at least for the next decade.