A multi-layer record carrier and method of manufacturing thereof and
recording thereon, includes data written in units of blocks on tracks of
at least two information layers. A first guard field is written at the
start of a data block and a second guard field is written at the end of
the data block. The power in the focused spot in the deepest of the at
least two information layers is maintained substantially at an optimal
value, by setting the length of the first and second guard fields such
that the end position of the second guard field of a preceding data block
is located within the area of the first guard field of the succeeding
data block. Thereby, gap portions between the first and second guard
fields can be prevented. Alternatively, the length of the first and
second guard fields is set to be approximately equal to the sum of half
the diameter of a recording beam in the upper one of the at least two
information layers when focused on the lowest one of the at least two
information layers and a maximum allowed misalignment between the two
layers. Thereby, the area through which the beam passes in the
information layer is of a uniform nature, when user data is being read or
written. The at least two information layers are aligned by optically
measuring and aligning alignment marks, such as header spokes, at
predetermined measuring points.