Techniques are presented for calculating directly the scalar functiona
l determinant on the Euclidean d-ball. General formulae are given for
Dirichlet and Robin boundary conditions when d is even and the field i
s massless. The method involves a large mass asymptotic limit which is
carried out in detail for d = 2 as an exercise, incidentally producin
g some specific summations and identities. Extensive use is made of th
e Watson-Kober summation formula. The calculation of the finite-mass d
eterminant is also briefly considered.