It is not proper for a
" lawyer say something like ,"I present to you Mr. Atkinson,
a scientist and a witness in this case" " because in that case
that lawyer is testifying instead of the witness,
and then that lawyer then becomes an unsworn witness in the case.
Adverse counsel shoud object to that.
If counsel is offering an EXPERT
(e.g. an M.D. or an engineer, or a handwriting expert)
then he asks him about himself
and asks him to testify as to his curriculum vitae.
If the expert has a printed c.v., counsel will usually offer it into evidence,
after which he moves the court for a finding that the witness
is an expert in the applicable subject matter.
Adverse counsel might object, or request a voir dire of the court,
after which he objects to a finding of expertise, or does not.
After direct examination is finished, adverse counsel
has the opportunity to cross examine.