When Defending, whether a civil or criminal matter, one must know what one is defending agaist. The accused did not arrest or sue himself, hence the grounds on which a conviction or successful suit may be made is solely in the knowledge of the prosecution/plantiff.
To introduce oneself to the client, take a few basic facts from him or her is as far as one should go until such time as the actual statement is in your possession. This is to avoid taking a long and pointless biography and appearing rather unprofessional.
To put it delicately, some clients have very busy social lives. They complete a number of different engagements and may be uncertain which one is the subject matter of this particular case. It in no way enhances your defense when you have a long and confused liturgy full of information which is not relevant.
Wait until such time as you are seised of the actual statements, then put the salient points to your client.
In some cases, the statements conflict to such extent that no conviction or successful lawsuit can result, beyond denials or explanations, your work is limited. In other cases you must do quite a bit of investigation to ascertain who, what where, when.
Of course, without the physical statement in your hand you can’t answer those questions.
It is not particularly wise to get too much biography from a client, for, (to put it delicately) his memory might be a bit faulty and he might contradict himself. The less he says the less can be forgotten.
Once the advocate can limit the purview of the interview to pertinant facts which connect to this particular legal conundrum and no other, one can prepare the case without extraneous material.