Speckle pattern applications have grown up beside holography making use of the highly coherent illumination derived from optical lasers. Speckle has not been well understood and in many cases treated as noise and something to suppress as far as possible. To date a few workers have used speckle monitoring to detect surface stability and others have used speckle in spatial filtering to form a displacement sensitive system. A significant property of the speckle pattern, namely its ability to carry wavefront phase information seems to have been missed until Leendertz published work at the I.C.O. Conference in 1969. In contrast to this applications of holographic interferometry have been progressively sought out, developed and used, since the early discoveries in 1964. The hologram has promised great potential in engineering metrology but has been disappointingly slow in finding its way into system design and industrial application. In the author's opinion this may be due to several basic practical difficulties with holography some of which can be overcome using the new speckle pattern methods. To establish this some of the metrological requirements must be considered together with fundamentally different recording practices which can be used for holographic and speckle pattern interferometry. It would be desirable to carry out all data processing rapidly and preferably avoid the uncertainties of the photographic process.