Using the dual laser plasma photoabsorption technique, the 3p region of Ca°, Ca+ and Ca2+ and the 2s and 2p regions of Ne°, Na+, Mg2+, Al3+ and Si4+, have been investigated. High quality spectra have been obtained by paying careful attention to instrumental effects and plasma opacity. For Ca+, the DLP data has been correlated with previously measured photoion results to obtain improved absolute cross sections. By using spatiotemporal maps, excellent ion stage separation for members of the calcium isonuclear sequence has been achieved. Comparison of the DLP data with independent Hartree- Fock calculations and data from other experimental and theoretical studies has revealed, for the first time, 4 features arising from the Ca°3p64s3d excited state and 18 features arising from the Ca+3p63d excited state. New lines of Ca+ 3p64s ground state origin have also been resolved. In the first systematic experimental study of the neon isoelectronic sequence, higher members of the 2s22p6 —> 2s22p5ns,nd series, not previously resolved, have been measured. Independent 2P3/ 2,i/2 thresholds have been established. The 2s22p6 —> 2s2p6np [P inner shell series has also been measured. For the first time, Fano parameters for low lying members of the series in Na+ through to Si4+, have been extracted. The Si4+ 2s2p63p 'P resonance has been found to lie 1.3eV below the 2P3/2,i/2 limits. Its profile is asymmetric which strongly suggests forced autoionisation. This is the first observation of this phenomenon in a laser produced plasma. Further evidence to support this assertion is presented. The near threshold photoionisation cross section for members of the neon isoelectronic sequence was recently calculated by Chakraborty et al using the Relativistic Random Phase Approximation (RRPA). The threshold photoionisation cross section for Si4+ was shown to be anomalous as a result of the downward movement, with increasing Z, of the 2s2p63p XP resonance below threshold. The predicted anomalous near threshold behaviour for Si4+ is supported by our experimental results. It is suggested that the phenomenon should also occur for higher members of the sequence as higher 2s2p6np XP series members successively move below threshold and that it is a general phenomenon expected to occur in any isoelectronic sequence where the outermost subshell is other than 1=0.