Marks' Standard Handbook for Mechanical Engineers (Hardcover)
The absolute reference to possess in all engineering and design. Too bad (for the version I have) that the units used are not always in the MKSA (metric, etc.).
Marks' Standard Handbook for Mechanical Engineers (Hardcover)
Mark's offers the Widest array of subjects of Any of the handbooks I've used. It has Consistently Provided concise and readable summaries engineering On Any Topic. It is The Most frequently used book on my shelf.