The last fifty years have seen significant progress in clarifying the philosophical issues involved in the Glendower, Regress and Taxicab Problems.  Indeed, several rigorous versions of the cosmological argument are available to overcome these.  The Gap Problem has yet to see as much progress.  Perhaps the reason is merely sociological.  The typical philosophical atheist or agnostic not only doesn’t believe in God, but also doesn’t believe in a necessarily existing first cause.  The typical philosopher who accepts a necessarily existing first cause is also a theist.  Thus there is not much of an audience for arguments that the necessarily existing first cause is God.  Moreover, it makes sense to proceed in order—first get clear on the argument for a necessarily existing first cause, and only then on the argument that this is God.            Probably the most important part of the Gap Problem is the question whether the first cause is an agent.  After all, if the First Causes were are all non-agentive necessarily existing substances that randomly spit out island universes, then the conclusion of the cosmological argument would be incompatible with theism.            In addition to the problem of personhood, there is the question of the other attributes that God has traditionally been believed to have: uniqueness, simplicity, omniscience, omnipotence, transcendence and, crucially, perfect goodness.  At the same time, it is quite reasonable for a defender of the cosmological argument to stop deriving attributes of the First Cause at some point, and say that the other attributes are to be accepted by a combination of faith and data from other arguments for the existence of God.  In any case, rare is the Christian cosmological arguer who claims to be able to show that the First Cause is a Trinity, and indeed Christian theologians may say this is good, since that God is a Trinity is a matter of faith.  Nor does the inability to show by reasoned arguments that the First Cause has some attribute provide much of an argument against the claim that the First Cause has that attribute.            There are two general approaches for bridging the gap between the First Cause and God: inductive and metaphysical.  Inductive arguments may claim that supposing that the First Cause exemplifies some attribute is the best explanation of some feature of the First Cause’s effects, and in doing so the arguments may reprise the considerations of design arguments.  Typical metaphysical arguments, on the other hand, argue that a First Cause must have some special metaphysical feature, such as being simple or being pure actuality, from which feature a number of other attributes follow.            Considerations of space do not, however, allow a full discussion of these arguments, and of objections to them, so I shall confine the discussion to the barest sketches.