This chapter has presented a survey of the alternatives to cellular-based systems for mobile data communications. The wide range of technologies and services receiving serious consideration and investment reflects the demand for mobile data capabilities. As technological advances turn dreams into viable commercial opportunities, some of these alternatives will prosper more than others. But none of them appears likely to replace cellular-based systems in the near future. In the next chapter we will discuss the most likely to succeed alternative to CDPD for mobile data networking.